Thanks Ksand,
For the first time in weeks i finally don't feel as anxious.
No problem
. For the most part, short trips of a couple of weeks are no big deal - because it's normal for people to take a 2-week vacation. Even if you have a GF in the UK, as long as you are only staying for a short time, have a return ticket and can show you have a job and a home to return to, UK immigration are unlikely to see any reason to question you.
So, as long as you are honest and have your documents to hand in case they do ask to see them, you shouldn't have anything to worry about.
Got to keep telling myself, all the horror stories are probably biased in some way.
The thing is that you are going to see a lot more 'horror stories' online than you'll see 'happy stories' because the people who have no issues getting into the UK don't go online to post about it, because they are off enjoying their holiday.
It's the ones who are detained and questioned and/or refused entry who come online to post about it and tell their 'horror stories' because they need to know what to do next and are usually asking for help.
The number of people from the US who are actually refused entry to the UK is extremely tiny.
Looking at the immigration statistics, just 1,845 of 4.59 million US citizens were refused entry to the UK in the whole of 2016... that's a 99.96% approval rate and just a 0.04% refusal rate.