How out of shape can one girl be?

I am realizing now just how out of shape I am since having the flu this winter. I have started walking 1 to 2 miles a day again, and my joints feel like I'm 80 years old. LOL. My physical therapist told me a long time ago that when your muscles atrophy (like mine have done from being sick this year), you use your joints more, and they have to start taking over a lot of the work. My knees and hips are very sore now, and I'm trying to build my quadriceps up to take over some of the work load. I am also doing some weights at home, and those dreaded lunges that are supposed to be so good for the gluts and quads. I really loathe getting back in shape after being out of shape for so long, but I know I will feel better when I do. I would like to gain about 20 lbs of muscle, but I know that probably won't happen until after my kidney transplant. 

At least I am on my way to being in better shape for the transplant.. and a big plus is... I'm sleeping better now that I'm back to exercising. It's amazing what a little endorphins can do for you!!!