Sounds like you need a change... First of all, tell your roommate to grow up and lock the door. That's not even safe and that's stupid to have to feel insecure all the time.
Get friends... people you study with, friends at home, etc. Try dating a bit.. Do things when you aren't studying-rent a movie now and then, eat different things, talk to different people, and get time some alone time.
Try to make your relationship with your parents stronger..
Keep studying and keep your grades up, it'll definitely be worth it!
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Together since 12/18/07 :)