Every. Damn. Night 
I wake about 2 hours after going to bed with an elevated heart rate and feelings of panic. It’s horrible. I’m only awake for about 5 minutes and I’ll normally grab an ice pack which calms it down. 
It feels like my heart beats out of my chest- my watch captures my heart rate at about 89 which I guess isn’t insanely high. 
Does this happen to anyone else? I can’t tell if it’s a panic attack or possibly to do with digestion? Either way I hate it.