Did your doctors say what sort of exercises you will be able to perform?
Are you cleared for both resistance and cardiorespiratory/cardiovascular training?
Thyroid and pacreatic issues are both tricky ... if your blood pressure, RHR and cholesterol levels are all decent, then consider moving from walking to jogging and then to running.
For resistance training, start simple and easy and move forward from there. Resistance could be as light as doing bicep curls with bands or a few push-ups or abdomoinal crunches depending on your fitness levels.
You said you do some jump roping. That's already good cardio.
As for diet I would consider a focus on nutrition, rather than a calorie count. If you have a disease condition, a focus on nutrition can help a lot. Consider reading any of Brendan Brazier's books for more on that.
If you are ready for somewhat intense exercise then I could give you tons of suggestions. But if you haven't exercised much in a while, start small and move toward basic exercises, such as hamstring curls, thigh extensions, bicep curls, dumbbell rows, lunges, and push-ups. Work on muscular endurance while building a very basic strength base, and once you are comfortable working within about 70% of the max you can lift in an exercise for 8-12 reps x 3 or 4 sets, expand what you do. At some point you will be ready for bench presses, squats, deadlifts, etc.. You can already do them, but try using just a bar or 45 lb dumbbells before going wild with it.
This post was edited by RewtheBrave on Aug 26 2014 07:11pm