How is a doctor, who could see hundreds of patients a week supposed to know ?
Personally I think our relationship with flu tells us a lot about the difference between our claimed ideals and our actual behavior as a society. We didn't want to know anything about it for curiosities sake and we invented all sorts of higher priorities to not study the mundane diseases between pandemics.
I really truly don’t want to be rude. I only want to point to the existence of literature on this.
There are results from molecular biology, from the various medical specializations, from population-scale studies.
There are certainly symptoms and biomarkers. There are documented changes to physiology, and there exists at least some information on how to help the body recover.
I got tested for other stuff - low T which I thought it might be or prostate cancer which the doc thought but neither of those. I'm recovering a bit through normal passage of time.
Also your anecdote aligns with the fact that it's more women than men who get it.