Sometimes when the fatigue hits, I'll realize that it is accompanied by a ton of stress -- the last time, for example, we had house guests, I was trying to play "perfect hostess" and get everything done myself... and was "struck" by fatigue. I was in the middle of washing dishes (by hand. dumb. I HAVE a dishwasher. It would have been SO simple to load it and push a button. But NOOOO.... I had to play "suzie homemaker" and WASH the darned things...)
Anyway, I digress. 
So I turned over the chore to my guests, and disappeared for awhile. A closed door to my bedroom, a half hour petting my furkids, and I was fine again for several hours.
But other times, the only thing that really will help is a lie-down. I may not necessarily nap -- sometimes an hour of afternoon TV, so awful I'm compelled to get up!, will do it. And sometimes a short nap -- usually no more than 20 minutes or a half-hour -- will be enough to revive me.
You'd think by now I would have learned how to better pace myself and not get in to these sorts of situations...but unfortunately it happens to me more than I'd like to admit. My husband is pretty good at noticing it now, and will step in and shoo me away...but other times I find myself struggling needlessly, when just stopping and letting it go is the best choice. I hate when I'm human. 