Fatigue was the symptom that sent me to the doctor in the first place, figuring I was just low on something.

There is just no word to describe the feeling. It's more/different than tired or sleepy, or even exhausted. Even the word "fatigue" somehow conveys the idea that it's the RESULT of something--hard work, no sleep, a bout with the flu, etc. MS fatigue is it's own bird--most of the time, there IS no such cause. You just hit the wall. Or wake up in the morning already flat-faced against the wall.

When you add body fatigue to brain fatigue, it something bigger than the sum of its parts. I'm going to have to invent my own word for when I'm too "tired" to think, too " tired" to care, too "tired" to care that I don't care, too "tired" to concentrate, too "tired" for fun not to seem like too much trouble. I'm just thankful that it still waxes and wanes.