Maybe it would help if you moved out muna, try living someplace else, at least for a while? Proximity is always bad news; especially when the other person has started dating someone else.
Concentrate on work, try to find/develop a new hobby, do things that you really wanted to do but never had time for because you had to spend time with her before. This is the time to enjoy yourself and aim to be a better person
My friend also made a list why it was better that he and his ex are not together anymore, and whenever he would miss her, he would look at it and realize that it's better that they're not together.
Maybe deactivating facebook would be a good idea too? Bottom line is, the less you see her, the better
Oh, and start dating other people when you're ready