Beta, shutting down our brains seemingly inexhaustably horrible images is so difficult. And I find that rumination breeds more rumination.
It may be helpful to “set a timer” on that thinking.
I found it impossible to shut down the images all together, but had more success managing during the day when I said “I’m not thinking about that right now - I am paying bills. I’ve set aside time to think about that at lunch.”
Less successful at night, of course.