How do you move on after you realize your friend was not a real one?

I thought she was my best friend until she suddenly decided to ignore me for no reason. She's always been a negative and cynical person, but I was always able to see the good in her. A couple of months ago, we got into a fight because she was very mean to me cause she was having a bad day. I told her I was disappointed and very hurt but I still forgave her. Recently, I got a promotion at work and was transferred to NYC. She congratulated me and since then, has decided to ignore me. I called her many times but no response. I a tired of making an effort towards someone who obviously doesn't care. How can I move on and let go of the anger and pain in y heart? Life is too short for this.