We aborigines can only discuss our Dreamtime with others of our nation. Using the term "Dreamtime" to describe REM sleep is actually a little offensive - use two words, at least.
That would be hardly tolerable, I would try to find some kind of treatment to deal with it.
I used to have scary nightmares when I was very young then just within the last year probably due to a drug I was taking I experienced nightmares a few times again. Worst one was that I was coated with some kind of skin that was making me feel very hot and I started scratching at my wrist trying to peel it off.