I've just had a Damascene conversion; I now realize that this ME thing is all in my head.
My head keeps telling me that I ought to be able to do things (after all six or seven years ago it was no problem!). Of course, my body tells me in a most excruciating manner that I'm not able to do those things. The head starts grieving for the limitations of the body, the restrictions on any socializing that I used to enjoy etc.; so I try to exert myself a little more, the effects a couple of days later are devastating.
There must be something wrong with my head, it has the false belief that I ought to be able to manage these things!
Suddenly the remembrance, from long ago days when I studied philosophy, you can't derive an "ought" from an "is". Then I knew that my head was wrong, it's just a bad philosopher. I may still have ME but, I'm not going to let my head make me feel guilty about it!