I'm so sorry to hear of your plight. If I may be so presumptous to make a suggestion, have you asked your endocrinologist for a referral to a dietician to help you make the best choices to meet your nutritional needs?
As far as exercise, I have to suggestions for you to take as a grain of salt. The simplest and least expensive would be to purchase an arm ergometer, which looks kind of like two bike pedals on a stand and you power it with your arms instead of your legs. It would allow you to get in some movement and get your heart rate up which would be very beneficial.
Depending on your abilities, water aerobics may also be an option for you. I have seen people at my gym who are missing a leg who are able to do the exercises because the water helps keep you buoyant.