Know exactly how you are feeling. I have different sets of friends: those I go to the football with, those I have a quiet night in with and others who I just go out and get drunk with. Although I do have two best friends, I don't really feel connected because I suffer from depression and borderlin epersonality disorder - I constantly tell myself, and believe that I am not good enought for them and they prefer their other friends.
I stay at home, I'll watch tv, go online and I'll do naything but college work, it's getting quite bad at the moment. As for boyfriends, well - I've not been in a relationship since I was 16 and now I'm 21 - and even when I was in those relationships, I never went around parading the fact, in truth - I don't think I even enjoyed it. Now I have convinced myself that I don;t want a relationship, a few people have asked me out but I have said no - not the right people and I'm not in the riht frame of mind.
My advice is just to let things happen, I mean concentrate on your college work and ensure that you get to university. It will make you feel so much better if you manage to get there, you will be 18 and life will quite literally just open up for you.
Enjoy life when it happens, and take my advice of enjoying your last few months as a child, as believe me it goes all to fast when you're past 18 - and in about 6 months times you will be wishing you had stayed in, instead of digging into the overdraft.
Keep the chin up, you've still got everything to look forward to.