Of the bad points of having a chronic illness, exhaustion has to be near or at the top. The other things can be worse, but they usually don't last long. The fatigue brought on by exhaustion can be nearly constant. You can sleep & wake up more tired than when you went to bed. You can spend all your energy on simple things like showering or fixing something to eat.
Perhaps the worst part is the inability to communicate how fatigue is really like to someone who's never experienced it. They can't grasp it. If they can, they're probably suffering with exhaustion as well & will be of no help to you other than comradery. Exhaustion & fatigue are vampires that don't die when the sun rises. They're your own personal monster that most other people can't see or understand.
Cya..