I often have nightmares. I wake up with my heart racing. Then I can't go back to sleep.
It sounds like the nightmares you are having are pretty scary.My doctor gave me meds to help me sleep. I take Trazadone, and clonipin at night.

I notice the scary dreams have subsided for now. But I still wake up at all hours of the night. I don't get a full nights sleep ever.I hope everything is ok with your thyroid.

Anyways......hugs to you for talking about it. We are here for you so don't be shy.