I am in love with girl but she said no to me.... ?

I fell in love about 2 years ago with one girl at college but we didn't talk too much with each other.She give me smile at the examination hall after ending the exam & I felt I have a chance..then after we used to meet very rarely but she was definitely impressed by my approach & everyday I used to remember her in my mind all the day she is running.This year at valentines day I proposed her but she said no.may be she didnt expect it so earlier but now I just want her or forget her & I am just unable to do