I, too, have many terrifying nightmares. One of my therapist taught me how to analyze them so they made sense to me.
First, write down the major components of your dream. Then for each component, write down what each component is feeling about you and finally what each component is saying about you.
As an example, I constantly have dreams where I am only partially clothed and running from someone, but getting nowhere. My legs hurt. There's a rail that I try to pull myself along, but it doesn't help. The environment is gray, nondescript.
The major components I used were partially clothed, running, person chasing me, leg pain, the rail and the environment.
Using "the rail", as an example, the emotions I noted were - alone, detached, unsupported, confused, helpless and resigned.
What I believe "the rail" was saying to me - I'm here, but I won't help you. You're not strong enough. You're on your own.
After completing this for the whole dream, I initially believed the dream was about the abuse I suffered as a child. I brought this to a therapy session and my therapist and I went over it. Talking it over with her I looked at it again and circled specific "thoughts". I realized it's was about the emotions I have not been able to let go. This made sense to me as I have been working on this in my therapy sessions. The dream also gave me incite into why I struggle with this. I did not have the support of my parents growing up. I was forced to swallow what was happening to me and as I grew up I thought that showing my emotions made me appear weak. I still feel my emotions, but I have never showed them ... even to this day.