I always feel that should listen to your body. This is extremely important especially if you are nursing an injury, medical issue or possibly pregnant. However, I also feel that you should always look for ways to safely move your body and continue to exercise.
Here are links to 2 resources for seated exercises. This includes 2 links, a seated cardio routine and a seated strength routine. Maybe you think doing a seated workout is lame or not worth your time. I say give it a try. I am sure you will get your heart rate up, burn your muscles out and maybe even work up a sweat.