I Suffer From Extreme Muscle Exhaustion. The Simplest Tasks Just

I suffer from extreme muscle exhaustion. The simplest tasks just wipe me out and I sleep all the time. If I sit down, I fall asleep. If I'm in the car, my wife has to drive because I fall asleep. I've had all my blood work done last week.....thyroid is normal, heart is normal, kidney and liver normal, everything is normal, but I don't feel normal. This extreme exhaustion is unbearable.