Since the most common causes have been ruled out via blood work and came back normal. There are two things. One make sure that the levels that came back were not in the low and/or high of "normal" as this still can indicate a problem. Also ask your doctor for a sleep apnea test. As if you have sleep apena, this can cause you to become as you describe.
As far as that blood work, if the case is that it is in the low/high of normal, follow up with an endocrinologist as they specialize in this area.
Best of luck, Hope this helps, If you need anything else please feel free to ask. If you found this helpful don’t forget to click the *accept* button!
