Oh yeah! It is called ruminating and boy do I do that. It is like no matter what I cant forget totally or let things go out of my head.

A therapist I had suggested that I visualise these things into a big blue ball and then mentally open the toy chest, put the blue ball in there and close the lid firmly.

I then tell myself that I will think about those things later and set a time to do that.

It isnt easy and I know it sounds that way -- but it does help and it takes practise. It has helped me to cut down on the amount of thoughts that intrude all the time and also given me a space to deal with them so they dont permeate everything