Welcome to the world of TMD, my friend. Fatigue is one of the symptoms - just think what a workout those muscles and joints get from grinding, clenching, and stress 24/7. I don't remember exactly what my ortho said as far as pounds of pressure put on the teeth/jaws with clenching & grinding, but it was astronomical with definite fatigue. Chronic pain of TMD can lead to fatigue and depression too.
it creates bad impression at work. everybody would be thinking what a worker can i be....always sleepy, tired. but it is not as if i nv sleep. even if i sleep for 12 hrs, it is still e same.....