Same for me. (As I mentioned, I do have CFS/ME which new research says is due to a virus called XMRV. And Fibro.) I used to think it was due to Fibro, but now think that's minor and I think I can tell the difference. I don't know if it's true but I wonder if the Mestinon not helping is when my body runs out of Ach supplies to send to the muscles? I would like to try supplements that help Ach production and provide building blocks.

If I sit or lay in some odd positions, they are actually easier on my body. Because certain muscles of mine are not as weak apparently. But normal day to day activity is hard on my muscles. Just sitting in a chair or laying down in some positions.

I think when I'm not on Mestinon, my body is releasing adrenaline just to so it can do anything, and it helps for the immediate needs but that probably makes me weaker in the long run. I guess we discussed this part already. Mestinon makes me not have to do the adrenaline pushing and crashing which feels icky and unhealthy.