I'm not sure if I can help here but I SHALL TRY!
I used to have nightmare's alot nasty nightmares they would usaly keep me up for ages I was realy I tierd all the time. But my mom told me when ever I had one to stop thinkging about it. But that only sometimes worked. She also told my think about nothing or something nice or funny. I hardy have nightmares eny more now. But when I do I tell it to go away and block it from my mind.

Hope this helps! and I hope u get enough sleep now.

Nightmares are often triggered by an elevated pulse during sleep. Ways to reduce this is to make sure the room is cool. A hot room will raise your pulse and lead to nightmares. Relax your body and mind before sleep by reading (not horror). The process of reading also enhances REM sleep because of the back and forth eye motion involved. Avoid watching horror movies or playing violent games late at night. These can leave images in your mind. Listen to calming music. You can even do this while you read. I hope some of these help! :3

You're welcome! I hope you can sleep better. :3