How to forget about her...?

I'm really sorry, Charlie :( I know how you feel, but basically the only thing I can think of to say is try to distract yourself. Go hang out with friends and try to have a good time. It'll take a long time, but you'll start to feel better in a few months. You'll never forget her, but the pain will lessen with time. I don't know of any other ways to cope with it. Good luck, dude.