I Have Terrible Dry Mouth But Only At Night, I

I have terrible dry mouth but only at night, I do not snore and I don't breathe through my mouth, I use biotene toothpaste, gel, spray nothing help I wake up several times at night my mouth hurt I have a glass of water by my bed. I don't take any medication except Synthroid please help me .I thought you have great practice and answer on computer is you hobby what the disappointment