I think that's the hardest part Jules, accepting that this is the new normal. I'm getting there with that, because to rage against it makes things worse or as someone said you can visit Pity City, but you can't stay there. It's natural to be down on the really rough times. As you say physically and mentally it's knowing your own self, it's patterns.
I still get upset when I think how active I was even 2 years ago. I am certain perimenopause triggered the fibromyalgia and now the rheumatoid arthritis. The osteoarthritis is more an age degeneration so that's more ' acceptable ' in a way. But the chronic fatigue is a bitch all right! And Unfortunately the RA has attacked me worse in my hands and wrists so it's very debilitating in many ways.
Do we push things too far? Hell yes! Because an activity that's seems tame to most people is a wild day for those with chronic illnesses!
So weight as this thread started with, has crept on for me too and I know that doesn't help joints. However with losing the ability exercise enough, I have adjusted my diet again,but tbh, there's too much going on trying to stabilise the serious health things. The weight issue is at the back of the queue - but I hope it can be addressed at some point.