Depressed because of this girl??? help or advice?

So it started 2 months ago at the start of the school year. I met this girl who at first i thought was ugly and a slut. But once i started talking to her i immediately really started to like her. She has good taste in music, is really cute, artistic and everything i love in a woman. So i continued to talk to her every day and she seemed really open. But one day i found out she cut on accident when my friend were talking to her and her friend by asking "what happened to your arm?" then her and her friend had this long stare thing. But i still really liked her despite her faults. So i decided id ask her to homecoming but she said she was going with her friends allison and a few others i know, i asked a week and a half in advance so i thought i had asked to late. So i proceeded to talk to her and it was normal. But i couldn't hold it in so i decided id tell her i like herlast week. I didnt get a chance because we were always around people. So i asked her on email saying how i like her and even if she doesnt like me id like to be friends etc. and she said "its not that i dont like you, its that i dont know you..and you really dont know me...sorry :]" but this week she doesnt seem very open to me when i talk to her except on monday, she hasnt returned the last email i sent in that chain or the one i sent today. I really like her, but i always seem to get infatuated easily. I don't know what to do and im kind of depressed about it too. Every girl i like never likes me back and im at a small school of 300 people so i cant just go out and meet girls?? any help or advice is welcome