I suffer from PTSD due to my military service. I used to have horrible nightmares---all kinds of stuff, from grappling with an assailant with a huge bayonet in his hand, to walking into ambushes and getting shot to pieces, bleeding out, and dying, to driving a deuce-and-a-half down a roadway and getting blown to smithereens when I run over a mine.
The VA put me on Trazodone, which has worked miracles. It suppresses the nightmares, for the most part; I still have one once in a while, but nothing like I used to, and I haven't woken myself up screaming in a long time. I still dream, but I don't remember what they are once I wake up.
Trazodone is a pretty common drug when it's used as a sleep aid; maybe you might ask your doctor about it. If it helps, then great.

I wish you peace and restful sleep, my friend.