Hi Mary! I had rotator cuff surgery last year and send you my sympathies.
It's a long, slow recovery. The only exercise that I was allowed to do for the first six weeks was ride an exercise bike. I did 30 minutes twice a day. After that, I slowly moved to the elliptical but had to be careful because that movement was painful at times. I added in leg exercises around the sixth week, such as leg press, extensions, and curls.
I discussed all this with my doctor and physical therapist, of course! I assume you're going to PT - maybe they can help you with exercise ideas?
It's taken a year for my strength and range of motion to get back to where it were - on all but shoulder exercises, I'm still a little weak there. Hang in there, it really will all come back even though it doesn't seem that way now.
Since I couldn't exercise as much as usual, I was super careful with my calories. But it's very hard to avoid the feeling sorry for yourself eating, I know!
Best of luck to you in your recovery!