Thunder thighs symptoms and conditions

I have been on seroquel for about a year now. i have thunder thighs and a belly that i never used to have before. and the nightmares are horrible! I have very vivid dreams and wake up a lot in the night scared. i have even passed out once cause i got up too fast. i go to the bathroom a lot and am really really thirsty all the time, it is like i cant get enough to drink. i am scared to get off the med but want to start going to a lower dose. i don't sleep very well at all anymore.