I Have Very Dry Mouth In The Morning, Lasts Most

I have very dry mouth in the morning, lasts most of the day. My blood sugar is around 110. I am overweight, and trying to lose by going to weight watchers. Have lost some, by it is going very slowly, even though I DO eat according to the plan. I am fairly active also, doing lots of yard, gardening work. What is cnausing my inability to lose weight and the extreme dry mouth?