How to stop ruminating on past thoughts and feelings and which ones were real?

How can I deal with False Memory OCD? I am struggling with ruminating thoughts, and trying to figure out false memories! How can I enjoy my day without figuring it out?

Ii spoke w my bf this weekend and he mentioned that he has thoughts just like me, but his don't bother him like me. I then felt a lot better and he tried dissecting one of his thoughts like I usually do and realized it felt more real for him after. That made me realize that none of my thoughts were ever true and I blew them up. However, yesterday I had a thought ab “wait wut if you liked that one guy? How dare you bc youre supposed to love your bf and not secretly like someone else” and treated it as I usually did bc I accidentally wanted to see if it was true but didn't rlly but I would check to see if it was there and now that thought feels so so so real now and I feel really bad how do Ik it's not real? I feel so bad and guilty bc lividly this makes 0 sense but it feels so prominent. It felt pretty real when it happened yesterday too. And now I feel awful bc how is it possible after my clarity the other day? Why does it feel so prominent 😞😞😞

I ruminated too much this morning and got distressing mental images (and confirmation) which sent me spiraling again. How do I stop thinking about this and how do I get back to myself? I feel destroyed.