I was having the same problem and it was found that I was getting low blood sugar. It is not normal to get this when you are sleeping because your liver should be able to prevent this from happening. You should see an endocrinologist to have this checked out.
LOW Blood Sugar... Try Eating an apple or a banana before bed
A doctor told me you have the most acid production at night- don't know if that enters in. Is your thyroid function not in the hyper mode? (Thyroid regulates metabolism.) Is it possible you are not eating what your body needs for you to get through the night not hungry? A well balance meal, with simple sugar (such as fruit), carbohydrates, protein, and fat? First the body burns the sugar for energy, then the carbs get used, then protein, and lastly fat is used. I know the problem from personal experience!