In the last year we have heard a lot about "Long Covid" and brain fog.
I have a lot of sympathy for sufferers as I have had brain fog for 7.5 years following my stroke. Every day, along with the near constant tiredness and giddiness, I have brain fog.
It is like doing things in a near constant state of exhaustion and drunkenness. Things mental and physical that would have been easy years ago are now hard. Doing any amateur radio design and building is now incredibly taxing.
My best description is like being drunk all the time: it is hard to do even the simplest task. With willpower jobs gets done, eventually. As an example, I am trying to find an intermittent fault on my son's electric lawnmower. I have had this all winter, but have not felt the energy to undo the screws and take a look.
I have great sympathy for anyone with a hidden disability. Outwardly we look fine to the world whereas inwardly it is a totally different story: we do all in our power to seem fine, but we struggle.
We do not like to moan, but it is very hard when others think you are fine.