You really need to find other things to do with your time. The only thing that will make you feel better is getting on with your life. She was never worthy of any of the time you spent on her in the first place. There's a whole world out there for you with friends, families, hobbies. Don't let a silly, doltish girl continue to have control over you. Put your time into other things like you did before you met her. When your life is busy, you'll find that going no contact and letting her go will be easier.
“This planet has - or rather had - a problem, which was this: most of the people living on it were unhappy for pretty much of the time. Many solutions were suggested for this problem, but most of these were largely concerned with the movement of small green pieces of paper, which was odd because on the whole it wasn't the small green pieces of paper that were unhappy.” ― Douglas Adams, The Hitchhiker's Guide to the Galaxy