When someone upsets me, rumination is a very bad habit of mine too. My brain obsesses without me even being aware. I get too tired to take notice.
These thoughts interupt my sleep too. Grrr
Lately panic has been creeping over me regularly with hot sweats.
I think overthinking is our way of trying to prepare ourselves for the possibilities that lie ahead. I am not so good at dealing with the unexpected and like to prepare in advance but spend too much time worrying about things that don't happen.
Sending hugs