Hi Lefthanded,
Most of us experience MS Fatigue, then if you keep on going past you point of fatigue, it leads to exhaustion.

Having said that, I also want to say to get a good check up from you PCP. It could be an added problem, like sugar, high or low, Thyroid, high or low, vitamin deficiently of some kind, lack of absorption in the intestines, not eating properly, like the right foods for energy.

So yes, MS can cause this exhaustion, but so can other issues, disorders, and other diseases. When I relapse it causes me to be exhausted, well beyond the fatigue mark. So I sleep when I can, wake when I do, and sleep again until it passes.

Some medications can cause exhaustion, even those for MS symptoms, like Baclofen, etc. even antihistamines, OTC meds, and other Pharmacy drugs can cause this too.

If you have a busy day, or work, try to cook or clean, have a family or animals to tend too, you have a busy day and it can be expected. If you are a couch potato, or in bed, that too can lead to being more tired than normal. Less activity does not build up stamina.

These things I have found to cause exhaustion. If I am busy one day, I rest the next. Too many consecutive busy days, can surely be exhausting.

Find out the cause and work with it, that's all you can do.
Take care, and rest when you feel this way.