Going on monday and worried about my mother

You're one step ahead of most people with having a letter from your boss Good on you!  Just stay calm and answer all their questions honestly. I also have found that if I'm dressed nicely (not dressed up but a nice shirt and trousers), I get treated a bit nicer by the I/O. 

Your mom sounds extreme and overly dramatic, just like my mom! 
Since I was living on my own, I didn't even tell my mom I was meeting a guy in person who I met online when I went to London. I went with my best friend, and as far as she knew, it was just a regular holiday. Too bad you can't do that! I told her afterwards that I had met someone in person that I had been speaking to online and she took it pretty well. I guess she understood that I just didn't want her to worry.
Anyway, it seems that you have everything in place, now all you have to do is assert yourself as a free-thinking adult and get on that plane! As others said, she may be angry with you, but she will get over it. Good luck!

Thanks! I'm looking forward to going on Monday. I just need to get out of the house! I hope everything goes well. I'm nervous, yet excited about the trip.

LadyRebeccaJaneStClair- Thanks for the advice! I'll be sure to dress nicely when I go. I'll also try to stay calm.

Have a lovely time and hope it all pans out alright with your Mom

Thank you Colleen.
Well, today is the day. I have about five hours left before my ride comes. I'm nervous as ever because I'm wondering how my departure will play out, yet excited at the thought of going to England. I got everything packed and can't wait to walk out the door.

I also just found out my grandparents are coming over today. I don't know if it was planned on my parents' part to have them come or not, but I am still determined to leave.

Take a DEEP BREATH....It will be fabulous, everything will work out....
ENJOY your time and just check in like an adult to say you got there ok ;-)

Geez, I really hope they let you leave! Sounds very fishy that the G Parents just happen to be popping by. You should have a friend or the person who is taking you to the airport come a bit early just in case they try and lock you up. Best of luck with the parents and I really hope you have a fantastic trip!

So far no grandparents arrived yet, so maybe it was a lie? I'm taking deep breaths and trying to be as calm as possible. Should I just walk out the door and never look back? Or say a few words to my mother before going off?

I think you should at least say goodbye to your mother before you leave!  Walking out the door without saying anything seems a little childish. 

Try and make an effort to say bye. If she starts throwing a fit give her a hug and tell her you will call when you get there and leave!

I would definitely talk to your mom, tell her you will call when you land, or just tell her that you are not trying to hurt her in anyway.... its tough. Is your dad in the home too? Moms and Dads are so different.. My mom is very smothering to my brother, looking from the outside in I saw how she ruined my brothers first major relationship. Sometimes its a power struggle with moms, they are so used to being the center of the universe and then you grow up and even in all your honesty they will never understand that sometimes they hurt your feelings.

We're in an argument now...I tried talking to her but it's not working at all...she's very angry with me and swears that I am not going today. I am trying to remain as calm as possible. My ride comes in a little while and I don't know how am I going to go. I am thinking of calling the police, but I do not think they will do anything.

Ouch, any chance of meeting your ride at a coffee shop or somewhere less dramatic. Sorry to hear its not the best sending off

I don't really think the police will help much.  I agree with Colleen - can you meet your ride somewhere else?  It might help diffuse the situation if you are not there when the ride arrives.

don't open that can of worms but I would just leave...Its sad and it seems hurtful but it will be better.

((HUGS))