Man, Lemme tell you what I did and that helped me a lot.
I deleted all my social networks (Facebook, Pinterest, Istagram, everything). Also, I deleted her from my WhatsApp contacts. I didn't want to see or read anything about her anymore.
I did it because I knew that if I only saw a photo that she was in, I'd stay bad.
As a psychologist said to me, the human mind needs to live brand new things, and kill the past that hurts. If you don't see new things or visit new places or meet new people, you mind will stay stucked in your past.
So I killed her in my mind (metaphorically).
I also moved away from every common friend that I had with her. I knew that they would remind me of her, and it wouldn't be good for my health.
I tried to make new friends, or improve the friendship with people from other places, that didn't even know her.
I will tell you a thing as well that no one's gonna tell you: don't jerk off thinking about her ass. Really. If you do that, it may be pleasurable at the moment, but you will stay even worse than you're already are. Also, avoid pornography.
Busy your mind with new dreams and goals, even if they are not quite relevant. It will help you as well.
Be strong. It was not your fault. She is a bitch, by the things you told about her. You deserve something better, lad.
Good luck and sorry for bad london.