Hey Michael! I have a few suggestions and things to say that I hope will help to ease your stress a bit. Happy to chat off AP too, just drop me a message.
I know that going to college is built up here (and in the UK too) as the be all and end all, the pinnacle to your life, and that choosing the right college will open the right doors for years to come.
That's just not true. A student like you will make their mark at any decent institution - good state college, MIT, Edinburgh, ETH Zurich (does that even do undergrads?). With your work ethic, drive, and interest in the world around you, you will succeed wherever you go. The old boy system might still be in place for careers like law, finance, politics, but a person with a good story can break into them later if they decide to. You'll find a niche, people like you, and thrive wherever you go. Just as long as you don't sit around regretting other choices you might have made.
Second - as long as the applications don't cost an absolute ton to make, just apply to everywhere you think you might want to go. Some dream places, some that may seem more down to earth. You're awesome, but not everyone will give you an offer. That way, the field is narrowed without you having to constantly rate the pros and cons and keep yourself up at night. Let the admissions panels do some of the hard work for you.
You then have a good amount of time to accept or decline the offers that do come through. You can sit down with your parents, think about finances, loans, bursaries. Different things (such as grants specific to an institution) will be available for the different offers, and it's difficult to make the decision until you know the concrete reality of how you would deal with going to that place. No point spending three weeks worrying about a place now - that place could still say no!
I'm sure there was more but the coffee is only just making it to my PFC...I'l be back if I think of anything else.
I can't help with the meditation though, I suck big time at anything that involves clearing my mind!
Alex: I think it helped, it was definitely relaxing to just sit and do nothing.
Becky: Thanks for the input becky, your words helped a lot!