It can feel like "flu with a hangover", that's my experience too.
In my case that's triggered by too much activity. I've gradually learned to stay within my limits most of the time, so these days I don't have the flu feeling as often as I used to. Although I have to limit activity to a handful of hours per week in order to keep it at bay.
In my case that's triggered by too much activity. I've gradually learned to stay within my limits most of the time, so these days I don't have the flu feeling as often as I used to. Although I have to limit activity to a handful of hours per week in order to keep it at bay.