Sounds disturbing.
I have no wisdom here, but last summer when I came out of my three week coma they put me in for my surgery, I had THE most vivid hallucinations (or maybe they were just dreams...I dunno).
Some where terrifying. Some where pretty damn funny....at least my wife thought so because she heard most of them.
I don't really remember too many of them 'cause I was pretty much out of it, but a couple of the terrifying ones still stay with me. To me, they were VERY real (even the funny ones)...at least at the time the were. I thought dead people where coming for me....and I could actually feel them tugging and pulling on my leg.
After it was all over and I finally got to come home, I thought about all of those hallucinations I had. The conclusion I came up with was that my brain was trying to make some sort of sense of what had happened to me, where I was, the trauma I had been though and the process of trying to come out of all of that.
I don't know what you're dealing with, but perhaps your sleeping brain is trying to make some sort of sense out of something troubling you.
