I am a balloon.
I do not mean my body is inflated. Neither that I have swollen up, although my ME/CFS causes inflammation and my fingers can at times be swollen.
My ballooniness is more metaphorical. Having ME/CFS is like being a balloon with small holes in it. Sometimes you can have some more energy, but more pain and fatigue is the reward for a little too much increased activity, sometimes days after. The balloon might get a tiny bit bigger for a short while, but then it loses air and might even become smaller than before the very moderate "pumping up".
Heck, I can't even inflate enough so that I can let go and fly around farting. Bad balloon.