Anyone else?

I have this nightmare that doesn't quite repeat but comes close. I have it for about a week to 10 days, once a year or once every other year. It starts out the same every time but each time I have it, it advances just a little, rather like a serial. It remains the same for the entire run (a week, week and a half, whatever) and then adds a bit more the next cycle. I won't go into what it's actually about but it's not frightening except for the repeat cycle.
It's starting to feel as if it won't finish or worse yet, when it does, I'll die. Scary.