You broke up with her? So in the first place you're the one who ended up your relationship. And now you miss her presence and want to be with her again?
Well, there's nothing wrong with getting back with your ex but the question is "is she still single now?" If yes, then go ahead and try to win her back again just like the old days that you were trying to court her.
But if she already have a guy with right now then it's really a signed that you must fully keep moving on. The best way to forget about her is to hang out with your friends, be more active to church if not well at least you go there, spent time with your family and especially have a great time making yourself smile