First of all, i am sorry to break this out to you, the girl doesn’t give a shit about you and that’s the real truth.If she did, she could never take that step but she did so instead of hurting yourself, why not start living your life.
I am sure you fell in love with the girl but she didn’t because if she was, you cannot stay away from people whom you love, it is just not possible. What you went through, i have gone through that and i did all the things you did but that way i realised that i was wasting so much of my energy and time doing things just to get over with something. If i see your ex life, she is happy but if you see yourself you’re not.
You gotta love yourself first mate because if you won’t than who will? Instead of wasting your time thinking about that girl, start living.I have this video that i would like to share with you which i think will help you to get over with what you are going through http://viralexpose.com/motivational/this-video-shows-us-why-we-should-stop-worrying-and-start-living/

Also one last advice my grandfather gave me when i went through the same thing you are going through- He said me to focus on myself and give less attention to those who just needs you according to their behavior. Kristopher, it is time for you to live for yourself ..Goodluck bud