I've had this problem for years, and have been to a doctor before; however, she just said it was malnutrition. On minimal exertion my heart rate will spike up to the 150s. My blood pressure drops from normal while sitting to hypotensive (~80/50) while standing. I have been very moody and irritable lately, which I notice but cannot control. I sleep 8+ hours but am only well-rested a couple hours during the day, the rest I'm extremely fatigued. I have episodes where I get a fluttering in my chest.