Getting Over a Breakup

How have you successfully gotten over a breakup? I did not end the relationship and it was the most significant of my life. I feel confused and trying to understand why. I'm not sleeping well and my anxiety has decided to resurface. I'm ruminating. I don't have many people to go to about this. Please don't say I will find someone else, because I can't go there right now. And I know it won't happen anyway.