Getting my Butt handed to me!

I don't know if I ever said this or not, but my foot injury turned out to be stress fractures on the metatarsals. This of course means no running for at least 6 weeks. So in order to try and stay in shape my Dr. gave me a "nonimpact" workout regimen which consists of Elliptical workouts, bike workouts, and pool workouts. I figured these would be pretty wussy and would have to start from ground zero by the time my six weeks were up. Boy was I wrong! These workouts are seriously kicking my butt. I do a spin class once a week. I have been on the verge of throwing up during these classes. My butt is killing me too! You have to work out seriously hard on these items in order to get your heart rate to the right range. I wasn't aware a person could sweat while swimming!
I am not sure what this means for my running in a few weeks, but at the very least I don't think I will be huffing and puffing like I originally thought.