Nightmares are more common in children than in adults and when people are upset, worried, or distressed.
Do you have dreams and/or nightmares?
Do you remember them?
Do you write them down for future writing projects?
(I've done this...)
If you are having troubling dreams it might make you anxious about going to sleep. Some things you can do are tackle any problems that are worrying you before you go to bed, avoid diuretics, caffeine and too much alcohol before bed, establish a night time routine that involves winding down time, and remind yourself to relax and that it's not the time to worry. Managing Your Mind recommends counting backwards or counting your breaths. It also recommends tensing each of your body parts and relaxing until you have done your whole body.
On average adults sleep seven and a half hours. But that can vary. (Einstein needed more sleep than average and Churchill slept less.)
How many hours do you sleep at night? I write best after a nap... (I don't dream when I nap, but I do at night...)