(((((((((((((Rebecca))))))))))
First off, that exam schedule sounds BRUTAL! What an awful idea for the school to coordinate things like that. *shakes fist at school*
Second, what stood out to me about your post is that it seems as though you have lots of people around you that care and support you. I've lived away from home for 6 years now (just turned 21) and I'm lucky if I can get together with a couple of friends that I've managed to keep in touch with. That being said, I remember that feeling of being overwhelmed by the amount of people that want to spend time with you - especially family members.
As for the feeling of integrating many different "lives" ... I know how that can be too. The thing that I have to try and remind myself is that while those "selves" seem to be very much separate from what you see as your true authentic self, they are still parts of you, and sometimes things aren't as black and white as they appear to be on the surface. So how do you make those feelings better/seem more whole? I can't say as I have the answer to that one, but just trying to re-frame how I look at those "selves" has helped... even if only marginally.
Do you have an ipod/mp3 or even a book that you can occupy yourself with as a more solitary activity? Or what about telling your family that you just need some alone time? Go for a walk maybe?
Often times (particularly when I'm feeling overwhelmed/down etc), its hard to see the amount of progress, or even intelligence that I DO hold. Instead of looking at yourself as an almost 21-year old who has nothing useful to offer, is it possible to look at what you have accomplished? I know this probably sounds like pop positive-psychology 101, but even just from this post, I can see a young women who, granted has some struggles, is very self-aware, and knows what it is that is bothering her. I see someone who can acknowledge the difficulties of being both away and at home, and can put her feelings into words. I see someone who obviously means a great deal to a lot of different people, and while she can't sometimes see it herself, knows on some level that she IS worth it. Because you are.
Try to take it easy on yourself if you can. What you described doesn't sound like a piece of cake, and a certain degree of empathy is most certainly warranted.
Sending many hugs your way... you can and will get through this, just hang on.
Jacq