How do i forget about this girl?

So I have liked this girl for about a year now. I asked her out 6 months ago, she went out on a couple dates with me to be nice but she didn't want it to any further than that. After she broke up with me over an email, i thought it would be easy to move on since i had at least asked her out so i would not have regret...wrong. I continued to talk to her and she also acted like nothing ever happened, but i still liked her. Eventually, she basically stopped talking to me, except if she needed help. I knew she was using me, but i thought it would be okay because it would be something to hate about her, maybe to help me forget about her. Unfortunately, that is not working. It is painful to look at her from afar, knowing I love her so much and not being able to get close. I try really hard to forget her, but she's what made my days happy, she's always on my mind, and I can't stop thinking of her. What do i do? I am trying hard to forget about her, but the more try the more I realize that i still love her. I really think that the only reason i am stuck on her is because I never even had a chance with her. I really would appreciate any help!