I am so sorry you are going through this. It can be very unsettling and anxiety producing. Not to forget causes sleep deprivation due to not really get restorative sleep. I went through it for quite awhile.
It took another sleep study, (already use a CPAP machine then found I had a REM disorder) then weaning off of steroids (for Hashimotos), and trials of different night medications. I got off of ambien at night time and on to Clonidine. Clonidine seemed to do the trick.
I occasionally still have bad dreams but they are no longer night terrors or like you have described " can no longer tell what's real..." Part of having PTSD triggered like that when you are sleeping, could be your body releasing trauma. I know that probably doesn't help much because you still spend the next day not knowing what it real and what isn't.
Another thing I tried was Craniosacral Therapy. I found a doctor who specialized in it and had worked with people who had a history of PTSD and trauma. It is very subtle work but I really responded to it over time. It really helped with my return to that "delicious" sleep where you wake refreshed and hardly remember dreams. My doctors kept telling me, "There's always more we can do" so don't give up hope. Reaching out to medical providers for help until this is resolved is my best suggestion.
