How to get out of the post breakup sadness?

so It's been about six weeks since my boyfriend and I split up and I cannot pass a single day without my brain replaying all memories like very often

And i don't know why its like the weird small things for example specific words he said in an argument from like three months ago, his actions etc, whether I was too distant in that one week when I had deadlines. I study psychology so I know there's a name for all of this, I know what rumination is, I can explain the cognitive process behind it and that somehow makes it even more frustrating because knowing doesn't stop it.

The worst part isn't the sadness, it's the feeling that if I just replay it enough times I'll finally find the answer. Like if I just examine it from one more angle, I'll figure out who was actually a fault or what I should have done differently or whether it was even real. idk I just end up more exhausted each time.
I've been journaling, which helps a lot. I've been going on walks with my headphones. I deleted instagram off my phone because seeing certain things was making it so much worse

The thing that really gets me is that it doesn't even feel like grief anymore, it feels like detective work I can't stop doing even though I know its finished.
Has anyone actually gotten out of this kind of loop? The sadness part etc, because I've read so many posts on that and still struggling