Paula, i am so sorry for what u are going thru. caregiving is a tough, tough job...but listen to the others--u have to take care of yourself as well--or u wont be any help to Jim.
even if its a few minutes to get out and take a walk (at night--it is Texas and if your knee permits).
I know time is not your friend right now and there never seems to be enough of it, but it will do u a world of good to take a few moments for yourself.