Don't mean to bring you down, but be glad you don't feel like that all the time! We folks that have the illness misnamed CFS (chronic fatigue syndrome) feel like that 24/7 365 days a year. Most of us started off with what seemed a regular flu. A lot of us tried to "push thru" as we didn't want to give in to illness. Please take care of yourself and don't push too hard. It can be self-defeating.
I hope that none of you who are ill now are cursed with CFS.