I have a few ideas.. no matter how cold it is outside, you should keep a window open in your room when you sleep, but not wide open, just a little bit ,so fresh air can come in...
before you go to sleep, don't eat meat or anything that comes from an animal ,best is if you don't eat anything 2-3 h. before you go to bed... and make sure to drink water or fluids before going to sleep 0.5L -1L...you will have to go out to take a piss in the mid.of the night ,but that is better than having nightmares..... these work for me...if you still have NM.-s ,then something is wrong whit you...