My husband also has terrible nightmares where he flails around and hits things like walls and me lol. He is usually dreaming about the abuse he suffered as a child or about fighting with his brother who is trying to kill him. Apparently when I have nightmares I hold my breath unintentionally until i wake up. Something you might try though is a dream journal or a calming box for when you wake up. Writing down your dreams bring them out of your head and helps you think of them differently. A calming box will help with you calming down when you wake up frightened.