Hi. I have it too. I spend hours re-living whole conversations and interpersonal situations, looking for things that went wrong, so I can fix them. It is to do with a fear of rejection, failure &/or abandonment. Because we have experienced any of these in the past we try to guard against it re-occurring now. We think if we can pick up problems at an early stage that we can solve it and stop it from continuing. I don't think it's OCD, well not the conventional OCD anyway. It could be more to do with your constant need to over-analyse everything, which you may be doing to try to take back control of what you feel out of control in ie the world, yourself, your life, others etc. Does this make sense? I hope so.
Anyway, you are not alone. I do it too. You just need to try to understand why you do it and learn to gradually decrease doing it. Your time can be used so much more productively.
Good luck and take care. Have you told your T about this? They may be able to give you some tips on stopping the behaviour.