Yes, I have experience of similar. The cause of your ruminating can come from any number of reasons. In my case it might relate to my Personality Disorder, in your case it could relate to OCD.
Often situations like this have completely consumed me. I have difficulty letting things go, in many ways I don't know how too. Recently, someone wrote a quote on the Forum that helps me
"Letting go is not getting rid of, letting go is letting be"
I think it is harder to be on bad terms with people. I have enough worries without being consumed by petty squabbles I may have with my peer's. What would help me to draw a line under something like this would be a cool-headed confrontation, even if that is just to clear the air. As soon as I made contact with the person, much of that obsessive irritation would disperse