Deep thinkers (those who like to investigate for answers) how did you stop rumination ? This is hard

Definitely tricky. I would start by trying to identify the question or questions your OCD wants you to answer first. Try to be vigilant for when these questions come up. Notice it as soon as you can and then try to resist answering it. When I get stuck like this, I respond by saying "I'm not answering that right now" or "I don't know, I have no way of knowing that and I'm not answering that question". Something along those lines might help.