I do that a lot. The doctor finally gave me Klonopin to help with the anxiety that those racing thoughts bring. I have a couple of past relationsips that I obsess about and they were so long ago that I should have let them go by now. I made a lot of bad desicions when being manic. Therapy does help work through some of that. I'm not as bad as I used to be. Now I obsess over money. I think it is just another symptom on anxiety and whatever it fixates on.