you're still in the first 2 years of the disease right ? things seem to be more volatile then, then I think the body can reach a new equillibrium. Some would say that there are predestined categories though.. mild, moderate or severe and its just a matter of time to find out which type you are, possibly it varies depending on genetics. Do you differentiate between crashes and PEM ? when I crash I struggle to play even the most unexciting video games like Farming Simulator or listen to a lot of music and I move extremely slowly and have bad orthostatic intolerance / weakness, but bad PEM is quite different .. I am still semi active but my stamina drops and I get all sorts of symptoms, high heart rate, bad memory irritability etc.
I was crashing a lot a few monthes ago but not at all now, I don't know why as my lifestyle hasn't changed much, I did remove a carpet from my bedroom that I was particularly allergic too though. PEM does vary and sometimes you get more or less than you expect from activities, you can learn some subtle signs though that its not a good idea to push things at certain times.
I know exactly what wolfcub means, but it very rarely happens to me ( sometimes just before a crash perplexingly ), its like a temporary remission, I actually experienced it yesterday / this morning, it was like I couldn't feel any of the pain or fatigue anymore, 75% drop in negative sensations, I felt light and springy and not weighed down and slow. I can still tell that exertion is damaging my body though, so its not like the disease mechanisms are all being switched off. It could be because changed sleeping pattern, caught asymptomatic coronavirus, rested more, or a result of overexercise ( which has lead to disease progression in the past * ).
The day before that I felt really rough and I probably looked like the living death to other people, didn't even feel like driving my mobility scooter but I had to go somewhere. I should be really ill still because I overexercised this week in a nightmare scenario where I was stuck in a field miles from anywhere, feet getting stuck in the mud, and had terrible flare up of all symptoms after, as you would expect.