I also understand how this can amp up latent body-image issues. I second the suggestion from arachne8x, perhaps there is some kind of low-key movement you can do... not focusing on calorie-burning or muscle tone necessarily, but more of a physical reminder that you are taking care of your body until it is well. Having gone through a bizzare joint-stiffening episode last Christmas though, I also understand that there are cases when even that seems impossible.

Alternatively you could try focusing on the fact that by working crossword puzzles you are strengthening brain muscles (seriously... I think I've heard that it staves off memory loss later in life.)

Even more seriously though, best wishes as you fight off the ick.