The most disabling part of the illness was learning that I can't just "push through" without paying for it for days afterwards. For months after, a single beer and a big meal would lay me out. You don't usually think of digesting food as strenuous, but in my weakened state, I'd start seeing stars and almost black out.
Now, it would be easy to dismiss me, blame me for not being healthier, but when young athletes who are fit have having these symptoms, and doctors (with better access to healthcare then I) are recording their own symptoms as scientists, it's not made up.
The worst part of having long covid is people (including doctors!) who don't believe long covid is real. Thankfully for long covid, there are biomarkers that can be tested for now so unbelievers don't have to take it on faith. After the medical gaslighting I've experienced, I really feel for people that suffer from fibromyalgia or other mysterious un-seeable maladies that there are not tests for.