CFS is very different. Fatigue as a word alone has different meanings to different people. They use it to describe the effect of driving for too long and you need a rest. Or a poor nights sleep. Or maybe you went hard at the gym or the bar. It is nothing like any of those things.

A good tell is that physical effort beyond a point makes it worse, and you need to stay within an energy envelope or you get severe symptoms. All activity is physical effort not just say running. Putting the kettle on for example or refactoring a line of code.

You know that nice feeling when you feel better after you’ve been sick. You don’t feel that ever again.