Don
My mom had double by-pass surgery 18 months ago at age 87. She is better than ever now. She was never much of a walker (unless you counted shopping at the mall) but now walks just about every day. She started out slow and has progressed to walking about a mile each day. On days she can't walk because of weather, she goes to the mall and walks there.
Cardiac rehab was tough on her at first, but it was amazing to see how much she progressed by the end of the 10 weeks.
One of the things she told me about 6 months after the surgery was how bad she felt before it and didn't really realize it. She couldn't believe how much better she felt. Yes, it was a long recovery, but now she feels great.
Keep going and doing what the doctors say. If she can do it, so can you!