I have had several episodes of waking in the middle of the night feeling like I'm trembling inside my chest, neck, and arms. At the same time my breathing wavers as I inhale and exhale. It's very strange. I don't feel like I'm shivering on the outside, but my quaking breath seems to indicate something is shaking. My husband actually woke me up last night because he said my arm was jerking and my breathing was weird. Has anyone else had this happen?