I don't know...I mean it's happening after stress when I feel relaxed and relieved it's over and I'm not really overthinking every detail or anything like that but I wonder if it can change your body chemistry or if I'm having bad dreams or something....the fact that it's occurring at the same time every time suggests it's a sleep cycle thing but I don't remember my dreams so I don't know if I'm in the dream part of sleep or not.