I found that when I wanted to do some of the things that I wanted to, on the physical side of my job, I couldn't do them. Or I could for a little while then just ran out of gas. My mind said sure you can, but my body said, No Way Jack!. That was probably the most frustrating part for me. I learned I had to get some patience, and I still have problem with that, I don't have enough.
Hopefully it will get better for you as time passes. Like my Dr. keeps telling me each time I complain that I can't do something I used to be able to, "you've been through a lot".