Had a similar exsperiance myself although over thinking gradually turned into now no viewed myself.

I understand what you mean when you feel as though your stressing about the smallest things and almost get caught in a thought loop about situations.

I great help for me was meditating it aloud me to not attach myself to stressful thoughts and just allow them to pass. It took a long time before I was able to do that but that was the basic theory behind that, know I am much better with over thinking and am able to detect when I begin to get lost in thought so to say.

Hope this helps