

I don’t know why exactly, but I imagine it’s similar to recurring nightmares about trauma. I had frequent ones following a horrible work situation. I’m a few years past it, but I still have an occasional one to make sure my sleep is ruined. I think of it as my brain compulsively poking a spot where I hurt over and over to see if it still hurts.
And/or blackout curtains as well. They pull double duty as an insulating layer, not just blocking light.