Hey girl,
I'm about to complete my first year of college, but reading your post brought my high school years flooding back! I totally understand how you feel--believing you are not good enough and never will be, pressuring yourself with perfectionism, knowing none of your friends will really understand and not being able to trust them with your deepest feelings, and turning to fantasy worlds to fill the gaps. I know, I know! It's awful.

I would strongly suggest you talk to a school councilor (lame, yes, but it's a decent first step) or, better yet, a psychiatrist or psychologist. I don't know if this is the case for you, but for me the thoughts and feelings you are having now led me to a highly self-destructive lifestyle and a suicide attempt. Fortunately I survived and was able to improve my lot in life, but it involved breaking down my perceived reality and building up a new, better one.

Some stuff that really helped me:
1. First, you have to WANT to get better. You have to WANT to feel better. When you do, you will have the power to change.

2. Stop telling yourself, "I should," "I could have," "I shouldn't." Recognize that perfection is a lie, and can only hurt you.

3. For every negative thought you have about yourself (EVERY. SINGLE. ONE) force yourself to come up with one positive thought to counteract it. Sounds corny, but this is all about changing your perceptions, and it does help. Looking at yourself in the mirror and stating those things that you like about yourself also helps.

4. Be kind to yourself. This is the hardest couple of years you'll likely face, and don't for a second feel like your feelings are invalid or foolish. What you feel belongs to YOU and you alone, and nobody else can judge or invalidate that.

I have no idea if that will help you, but I truly hope it does!! Good luck, and take care of yourself. College is so much better!!!! *hugs*