I fink im in love wif a gurl buh she lyks sum1 else and its reli depressing what can i do?

I think the best way for you is to remain her friend, be there for her when she is going through a difficult times of her life. Who knows? She could be falling in love with you in the future. For now, letting go of someone that you truly love is one of the hardest thing in our lives, you may want to move on and find another girl who can make you happy.