Honestly overwhelmed.

So I wasnt too concerned before I went.  But my experience is this:
Everything is new. Every one of my patterns changed.  Nothing is familiar.  I guess I underestimated the effect that would have on me.
Basically my stomach and chest have been in a near constant stress. So much so that it is very difficult to fall asleep. My brain seems to have a habit of thinking non-stop when trying to think. The thoughts are of any random things like doubts about the whole thing, family, thoughts of just flying back, or just thinking of what errand I need to do next.  Or just stressing about being stressed making it an unending circle. 
So my constant stress and apparent anxiety gets 10x worse when Im trying to sleep.  It gets to light hyperventilating/deep breathing and cold sweats.  Freakin almost impossible to sleep with that.  So over the past days Ive got a few hours in. 

Ive never experienced this level of stress and dont really know what to do.  I didnt expect it because Ive never felt anything bad beforehand.  Previous non-longterm visits were just fine.  Maybe its the more permanent status that is getting to me.  Whatever it is my brain wont listen to logic and keeps stressing over everything here in the uk exept the fee fleeting times Im able to think of something else.

I have nothing bad to say about the uk. Coworkers are great.  New apartment is great.  Everything is great and it is a great opportunity for my new and successful career.  But this brain wont shut up and keeps stressing me out with no end in sight all while preventing me from sleeping. I am not sure how much i can take.  If this is a continuing thing that doesnt go away then it is just not workable.  Im hoping ill adjust soon enough and get over this... Culture shock or whatever (i wouldnt say it has to do with culture but instead just my patterns all doing a 180 and feeling absolutely not comfortable anywhere despite nice peole and a great apartment).

Right now i am waiting it out but im not sure it has gotten any better. Its frustraiting and a bit embarrassing that im having such issues that i cant seem to control due to my stupid brain not listening to logic and reason.

Any suggestions?  I cant seem to relax or anything.  Time will hopefully be enough and maybe after i have all these errands done.... But geeze. Never been anywhere near this stressed.  Everything around me is for all purposes good and great. But my brain just wont stop stressing despite that.  Loooots of stress and i guess anxiety.  Almost no sleep.  Stuff that was never a problem before.

I need a cure besides time.  Though that probably doesnt exist. 

Poor guy.

You didn't just move out of your parent's house.  You moved countries. 

When did you get there?  Hasn't it just been a few days?  What has occurred in your life is huge.  It's going to take some time for your brain and body to settle down.  Your body clock probably hasn't even settled properly yet.

It sounds like you are having panic attacks.  You might try googling some natural remedies for that condition.  Before you try any medications. 

Don't try to digest it all at once--just take it bite by bite or it will be too overwhelming. I always try and think about how strange/foreign/impossible new things are when you are first learning them...think about how it felt when you first got behind the wheel of a car...scary, right? But now I bet you don't really have to think about it....that same ease WILL come with time. You just have to give yourself time

  That was always my mantra when I was learning to drive in the UK after only driving an automatic transmission in the US...everything felt so hard, and took so much concentration! But, with time and practice, I got my UK drivers license no problem and now driving in both countries is equally comfortable...so be kind to yourself, and take a deep breath. Enjoy learning new ways, and having the perspective to evaluate your old ways. You will become a hybrid and be glad to have expanded your mind. In the meantime, maybe try anchoring yourself with some daily ritual--like a run or something, that can keep you grounded and feel like you have at least one thing under your belt for the day.

I'm sorry that you are struggling.  Moving countries is HUGE.  A lot of people think moving is sexy and exotic, but reality hits and it's just a new life really far away from everything and everyone you know.  I struggled BAD between six months and two years.  I finally started to feel happy again after two years...  It was hard.

Give yourself permission to struggle.  You don't have to be thrilled by the move. 

Baby steps.  What about the move were you looking forward to?  What do you enjoy doing in your free time?  Try to plan something each week so you have something to look forward too.

Don't be too hard on yourself, it's early days.

So I wasnt too concerned before I went.  But my experience is this:
Everything is new. Every one of my patterns changed.  Nothing is familiar.  I guess I underestimated the effect that would have on me.
......
I need a cure besides time.  Though that probably doesnt exist.  

That is a dreadful feeling you're describing, and I'm so sorry you're going through it.  As I've done before, I'll simply make some observations based on my own experience and you can take or leave what fits for you.

I have a tendency to fight my feelings - something like this... I start to feel a bit nervous about doing something, then I think, "I shouldn't feel nervous about that, it's nothing to feel nervous about".  I've now added some "shoulds and shouldn'ts" onto my nerves (or anxiety, anger, you name it...) and the pile grows into something bigger.  I start looking for reasons for my thoughts and feelings..... well, you probably get the drift.

With some success I've learned to "let" myself feel.  I know it sounds silly, but it was me trying to use logic as an argument against emotions which tied me up in knots.  It sometimes helps to step away a bit and ask myself what I'd say to a friend in a similar situation.  I'm so much kinder to friends than myself, and give much better advice to them as well.  

Find something you really like - anything.  Annie.e and Rebeccajo have given great advice.  Something you can control, that links you to your former life.  Did you stop for coffee at certain times of the day? Did you talk a walk during a lunch break?  Whatever it may have been, try to bring it into your new life as an anchor perhaps.  

Skype (or any of the similar e-communication methods) is great of course, but that 8 hour time difference can be really tough.  Yes, I'm from California too - that's a whole lot of hours!  Like you, my fears grow largest during the middle of the night - well, they're up in California in the middle of the night here. Just a thought....  

Be good to yourself, you've been through a tremendous change.  It isn't all positive, no matter how exciting it sounded when you were in California where everything was familiar... it isn't all negative either.  

Edit: Include KFdancer in the great advice group! 

Wow, ok! I didn't realise you were going to be over here so quickly.  You posted only like 3 days ago about having received your passport back! 

Definitely be nice to yourself!!  You've not even had a chance to get used the idea of moving to the UK (let alone the time difference).  I think your first post was less than 1.5 months ago-- so to have packed up your life and moved over at a moment's notice is kind of a big deal, and definitely wouldn't have been easy for anyone. 

I had a long time to get used to the idea of moving to the UK (after doing a study-abroad in the UK, the boy I fell for and I stayed together doing long-distance for 3.5 years), I made the decision sometime around April, then moved in September. I settled in okay, since I came as a student which was a good environment to make friends.  But I still remember one day, about a month in, I was in a Wilkinsons and had a bit of a panic attack while buying cleaning supplies, or something else that seems mundane.

It's stressful.  There are similarities between the US and the UK, but there are many differences too.  Brands have different names, or you're not sure which shop is best to find something, and finding an equivalent to something you couldn't live without in the US is damn-near impossible to get ahold of here.  But I promise, if you give it a chance, it gets better.

Start with the basic essentials if you haven't already: 

1. Stock your fridge/pantry-- if you can't fathom leaving the house right now, you can even order online and have them delivered to your door at a pre-selected time.  Try:  Ocado, Sainsbury's, or Tesco

2. Register with a GP -- your post does raise some health concerns.  If you continue to have difficulties, you will want to get it checked out.  You will need to bring proof of residence, a form ID (your passport will serve both purposes), and proof of your address-- if your work is helping with your flat, they should be able to help with this also, if you haven't gotten any mail yet. Find GPs in your area here:  NHS Find a GP

3. Set up a bank account if you haven't already.  This will make paying for everyday things much easier.  (Won't run into the problem of having to withdraw cash from a cashpoint because the cashier doesn't understand how a US card swipes..).  To set up a bank account, you'll also need proof if residence/ID/address.  Some well known banks include:  Barclay's, Lloyds, TSB, NatWest, HSBC, Santander.   Just a note that if you have an account with Lloyds for example, you can take money out of any of the other banks' cash points (ATMs) without a service charge.  Very few cashpoints charge you to take out money, unlike the US where you have to use your specific bank's ATM for any transaction to avoid fees.

4.  Find your way around town.  Last week's tube strike probably didn't make things easy for your arrival here, and another is supposed to start tonight.  It is definitely a hassle, but not exactly the norm.  I strongly suggest downloading the CityMapper app for your phone.  It has been a lifesaver for me more than once!

London is a massive city, which can be equally overwhelming.  Take your time getting used to things-- like your neighborhood, the way of life you'll become accustomed to, and how you respond in these new situations/environments.   Like you said, even the little things are going to be a bit different here.  Growing up in the US, I never thought I'd be hopping on a bus to buy groceries, or plan ahead to do laundry (because each load takes 3 hours and even then isn't even fully dry!). 

You've only been here a few days, therefore I do suggest you stick it out at least a few weeks.  I definitely think you're experiencing the culture shock that comes with the idea of being more permanently based in the UK (which can be terrifying).  Try not to stress and think "OMG, What Have I Done?!" Give it a chance; there may be things you can never get used to, but you don't know until you try.  Personally to relax, I find red wine and bubble baths a great help  

Best of luck to you-- Thankfully you've moved when the weather is a bit nicer and warming up (and staying bright outside longer), so at least it's that little bit less depressing! 

The GP suggestion is good. Ambien (or whatever it is called here) might help you sleep. You are probably exhausted. Jet lag can last a lot longer than you think.

Stay hydrated. Long sturdy walks/exercise. Eat properly.

I had a rough time of it, broke down and cried a few times.

Jet lag can last a lot longer than you think.

Isn't that the truth?  

When we went home the last time, it was a visit to hometown plus London.  We did the first week in hometown so we could be physically adjusted.  We didn't want to lose part of our 'tourist time' in London sleeping and/or otherwise getting acclimated to the time difference.  

Pickled Sakura mentioned something else I hadn't even thought about.   Superman did first post here so very recently.  He's 'upped sticks' in practically record time.  No time beforehand, probably, to do all the stuff most people plotting an international move do.  Meaning - stress out about it!  :p  Some of us have had YEARS to think about these international moves.  We ask questions about where to find this and that; how to hunt for housing; how to open bank accounts and other of lifes practical issues.  Superman instead is working everyday in the US, getting his passport and flights organized, packing up his stuff, and - boom.  All of a sudden in the UK.

I know full well that I have an overblown love affair with the city of London.  But if I were Superman - this is what I would do.  I would say to myself - my God, I am living in the most wonderful city in the world!  So much to do!!  So much to see!!  Once I can get my bearings, there are green parks for me to relax in.  There is something every night I can go do, see or hear.  Heck, I can just sit down nearly anywhere and amuse myself with people watching!  Food of every variety - likewise drink.  And I don't have to drive anywhere myself.  

Try to think positive.  IMO, you are in an awesome place in which to do it.  Overwhelming maybe.  But at least not stuck out somewhere in the boonies.  :p

I'm not in your shoes yet, Superman, but I am watching your posts closely because I will be going through something similar in July. So I don't have a ton of advice except to echo something that Becca said. When I'm feeling a lot of anxiety, much of it has to do with the "should" feeling - I should be happy, I should be enjoying myself, I should be on top of things. The first thing my therapist said was to let that go - how I feel is how I feel, and that's just fine. (Unless those feelings are dangerous, obviously.) The middle of the night is the worst, everything always feels a hundred times more daunting then. What I try to do is breathe deeply for several breaths, and tell myself that it's okay to feel anxious, name the primary cause of my anxiety at the moment and pick a tiny piece of that cause that I can manage - and then plan to handle it in the morning. So for me, as I was dealing with postpartum anxiety, I would say "yes, it's scary to think of being home alone with a newborn all day. That's okay, because this is new to me, and my brain chemistry is wonky right now. Tomorrow after my husband goes to work I will take a nice long walk with the baby and get a coffee at Starbucks..." and I'd just give myself a routine for the day. Even if we didn't stick to that routine (babies have their own ideas), it helped to calm my brain down in the middle of the night.

Medication also helped me, if your anxiety is really crippling you and medication is your thing. Hang in there, I hope things improve for you soon!

So you brought the good weather here with you and we have you to thank for a three day Bank Holiday weekend with no rain?  Well done!
You've just done one of the most stressful things you could possibly do, so the anxiety isn't a surprise.  That it's worst at night isn't either-I can be wiped out, and then the minute my head hits the pillow, my brain goes into overdrive.
Try wearing yourself out, go for a long run down on the river, or take a couple of intense classes at the gym.  Bach's Rescue Remedy is worth trying, and, if you can get some from a GP, Zolpidem (Ambien in the US) will help you sleep for a few days til you settle down some.
If it helps, I was in the same shape as you were when I moved here and cried every night for at least a month.  That was in 1994.  It gets a LOT better, promise.

Having lived in 3 countries and sometimes struggled to adapt, I totally agree with the suggestion of just getting out and appreciating the city as if you are a tourist.  Of course you will have errands to do, but if progress slows down on those, don't get frustrated - go out, ride in a routemaster bus or a London taxi, go to a museum, the palace, whatever.

Lack of sleep is horrible of course.  As others have said, maybe you can find a natural remedy, or see a doctor.  I would add that you shouldn't be afraid to ask for time off work if you need it - either to run important errands, to see a doctor, or simply to rest.  It's in the company's interests that you remain fit and healthy, and on this side of the pond.

It's completely normal to panic at a time like this.  It doesn't mean you've made a huge mistake.  It doesn't mean you can't hack it.  It just means you're aware of this ginormous change in your life.

Stuff like this hits most people, at one point or another.  Often at several.  There's the initial 'OMG, where do I go, what do I do' shock.  Then, for many people, there's another bout of it 3-6ish months down the line, when it finally sinks in that this is the long-haul.

To be honest, I worry more about the people who claim they never had any trouble, never felt anxious or homesick or out-of-place.  It makes me suspect that they're either in serious denial, or not very bright.

As others have said, the first thing is to give yourself a break!  This can be tough if you're the sort of person who's used to having a very structured, 'together' lifestyle.  No one has it 100% together all the time.  You're allowed to be a bit scattered.  Prioritise your mental & emotional energy toward the things you really must pull off (i.e. your job, coursework), and feel free to live on McDonalds and Pizza Hut for a week or two. (Never underestimate the comfort of familiarity.)

When you're ready to start establishing a new routine, then as KFdancer said, 'Baby steps.'  Make yourself a list of things you need in order to feel in control and settled.  Start with what matters most to you, whether that's joining a gym, finding your nearest comics shop, or stocking your spice cupboard.

As you tackle the items on your list, remember we're here.  There's a huge pool of knowledge (and luck for you, most of it will be local!) to help you find 'substitutes' for whatever you're missing.

Finally, as others have said, do try to take care of your health as best you can.  All this stress can really weaken your immune system, so take common-sense precautions (i.e. refrain from licking things in public), and think about a flu vaccine.  If you need help sleeping, but haven't registered with a GP yet, there are over-the-counter sleep aids you can get (Nytol, melatonin supplements, Benedryl) that might help.  And once you are registered, don't be afraid to ask your GP for help.  If you're genuinely feeling depressed and/or anxious, say so, and be open to help, whether it's a short-term prescription, or counselling.  (Never underestimate the relief in being able to vent for 50 minutes to someone who's being paid to listen sympathetically without interrupting!)

I echo the suggestion of acting like a tourist. I've moved to 3 different countries, the first time with children and having them to entertain while we did all the routine and boring stuff helped to push the anxiety away. After all, when you're looking at all the great sights your mind is occupied with something else other than your anxieties.

However, if you can't get past the panic I'd suggest going to see your GP, or a local walk in clinic, because you need to sleep and when you are rested I'm sure you will feel much better.

To be honest, I worry more about the people who claim they never had any trouble, never felt anxious or homesick or out-of-place.  It makes me suspect that they're either in serious denial, or not very bright.

Insulting. Everyone is different, and the experiences of people who are particularly adaptable are no less valid than those of people who have a hard time. I have never felt homesick or had more difficulty adjusting than I could handle, but I promise you I am not in denial and most certainly not stupid. I'm also not any better at life than people who have a hard time. Can we accept that everyone deals with things differently and not make any judgments about anyone's intelligence?

more difficulty adjusting than I could handle

This is the key.  I don't mean that, if you didn't have a major existential crisis, you're an idiot.  I was referring to people who might swear that they never even noticed the difference, or that everything is a million times better/easier/shinier here, and they can't imagine what people are so upset about, they must not be trying hard enough.  I was also attempting to make someone else feel a bit better.

I'm sure there were things that took you a bit of getting used to, and that you handled them.  And that's perfectly normal.  I imagine, since you've been here for a while now, there are also some initial moments you've probably forgotten about.  Which is also normal.  I can't recall you ever criticising people who've had real difficulty, and I assure you, I've never had any reason to doubt your intelligence.

So, I'm sorry if you took personal offense at this, but I'm standing by my statement, and it's intent and context.