First, getting over a girl you were once attached to can be a difficult time. Understand that it will get better with time, but you have to put an honest effort in getting over her.
Realize that she hurt you and it is time to move on. This means cutting off communication with her for a while (maybe forever). This may seem drastic, but if talking to her and seeing her brings back feelings, then you owe it to yourself to end any communication with her.
Also, work on establishing a healthy life outside of her. I am sure you already have a life outside of her, but continue to develop this. Join a gym, go to a local group/club etc. Just get out and meet new people. Eventually, you'll meet a new girl and you'll never look back at this one girl.
I found that running was a great way for me to just get things off my mind. It also helped me lose some weight and got other girls interested in me which always helps when getting over a girl
Good luck man