Were you tested for sleep apnea? This, to me, sounds like it may have been missed. As we cascade and climb through the several stages of sleep, our brain activity and our respiration rate and heart rates all change. However, sleep apnea disrupts those cascades and successive transitions, meaning terrible sleep, sometimes bad dreams, sometimes awakening in a seeming panic and wondering why you're behaving that way...when it's that your heart has sped up to get more oxygen to your system, and it's doing that because you're not breathing well...or at all! With no other evidence of endocrine system malfunction (including thyroxin levels and thyroid activity, no underlying or generalized anxiety disorder (from a formal diagnosis), and no problems with mattress, pillow(s), room temperature, no pathogens making you sweat and be feverish, if you're not in the habit of eating snacks within three hours of bed....those kinds of things...I think all that is left might be a referral for a polysomnography.