Have you considered that it may be an anxiety related issue? People who have anxiety often find night time to be the most difficult as it is then where we are lying in bed mulling over everything going on in life. I know that when my anxiety was untreated I could reach heart rates of 110bpm, which again felt like a hypo was coming on but my bloods would be fine. Now I have to check when I feel my heart rate increase to find out if I'm just feeling anxious or if it is indeed a hypo, since the symptoms overlap! It could be worth trying some meditation or relaxation yoga before you pop off to sleep to see if this helps. Also a mug of chamomile tea! Hope this gives you some food for thought.