I'm sorry your doctor didn't give you options. I can't take antipsychotics, they make me really weird... and I tried ONE pill of your med and even the doctor said enough. He explained some people sort of overreact to it. And they shouldn't take it. I assume your doc says you should take it despite your reactions. I was completely knocked out on it. Like you. Yes, it is supposed to be sedating but according to my doc that is not a normal reaction and calls for a different med. I wish I could beam him to you but unfortunately he's not even my doc anymore.
And, no. I had no effects on anxiety on it. Some do. For some people, it is the WRONG med. Personally, I get panicky from being sedated the wrong way. Benzos are often fine (not all of them) because they sedate my anxiety... just sedating my body will just make me feel like I'm sitting in a capsule in my brain while my body is dying.
I can so see how it causes nightmares.
I don't really know what to say either than that docs sometimes do not UNDERSTAND the pain they put us through.