Good afternoon Potsie!
My memory is not the best around, but I do remember your name here a while back. However I fail to recall, what your health issues were that brought you here in the first place!
When I see a thread like this, the obvious comes to mind, and I'm thinking you need to ring up the Dr and make an appointment.
I myself am 55 now, and I use to have great leg and knee strength, however; those days are long gone, and to squat and then come back up from it takes quite a bit of effort for me.
Your condition sound a little more serious though, but I wouldn't even venture a guess as to why with limited information here.
Lots of variables here, and too many guesses for an educated answer from me.
Sorry, I can't help, but I do wish you well, and hope you find a reason why. We just hope it's not too serious though!