You can try to put a sound on when you go to sleep. Something that would soothe you. It could be the sound of the rain or something else. You could also try audio books. It can also help to put something on your pillow like lavender or eucalyptus. Try to make your surroundings as good and as comfortable as you can. I hope you'll have better dreams soon.
I understand where you're coming from. I know this sounds rather cliche, but try calming yourself down before bed. I found that when I went straight to bed after a long stressful day I had more nightmares than good dreams. Now, I try and follow a nightly routine of pampering myself. I cleanse my face completely and light a candle while I read a book to put myself to bed (making sure to blow out the candle before I go to sleep of course!). I hope these methods will help - if not, I wish you the best of luck in finding a proper way to cure these nightmares!
Write down your dream, how it made you feel and why. I find that when my mind is racing or when I'm stressed out that writing things down calms me substantially. Works for nightmares too. Just keep a pad of paper and a pen at your bed and use it when necessary. Hope this helps.