I'm sure you are aware of this, but there's quite a lot of annecdote about patients having the initial trigger/infection, seemingly then on the mend for a week or two, and then crashing bad, and subsequently developing ME/CFS.
It's difficult to define the prodromal phase from the onset of the illness because the two overlap.
For me, on January 9, 2022, at 7 p.m., there were many factors that could explain the onset of the prodromal phase: mixing alcohol and tramadol, untreated Lyme disease, the COVID vaccine... I collapsed with my quadriceps completely paralyzed... they were vibrating. Then, two hours later, I experienced burning all over my body. And then hyperacusis, fatigue, brain fog, chills...
Twelve days later I caught Covid, then dry eyes and mouth, sudden and strange fatigue (PEM?).
It lasted, but I could continue exercising, which actually made me feel good, and have drinks with friends and work full time (work from my home, but very intellectually demanding - book editor).
They only found one thing out of 1000 tests that wasn't right: Lyme disease (positive Western blot, but old infection) and a moderately compromised blood-brain barrier.
Then in April 2023, I drank too much, took drugs, exercised two days later, and it all started. My body stopped working mid-run, as if it had changed. Then, two hours later, I had a tetany attack and panic.
I'm becoming intolerant to exertion and stimuli, intermittently, with panic attacks.
Did I already have MECFS in January 2022? Was it a "simple" shock to the central nervous system?