In the early years of illness I was able to recover from activity overnight. Now it seems as though PEM for me is becoming prolonged especially when I have to work. I just worked 3 straight days which is a lot for me. I got through them pretty good but now am extremely tired. I just can't do anything except sit or lay down. I never have any other symptoms with PEM except extreme exhaustion like I am just a total zombie. No muscle pain...flu symptoms etc...just exhaustion. It isn't even that I need to sleep because I can never sleep during the day but even walking is a chore. I do know that people experience PEM with just mental activity which seems to be the worse for me. How is it possible I can keep going for 3 days and not feel bad but then boom...I am guessing it is because I am finally not on the go and maybe the adrenaline is wearing off...or do I simply just always run on adrenaline and then it finally gives out. Does anyone here experience PEM with just really extreme tiredness and no other increase in any other symptoms or is this something else I am experiencing?