I just wanted to say how I agree with all who have posted so far.
When I had my appendix out, (which is NOTHING to what you had done!) I had to work gradually back to full days too. That was a blessing. I was so tired when I came for a half a day, I could not believe it. It was then I realized that going to work includes all the time at home preparing to go to work. So that could add on a few hours that are not even counted.
I hope your healing continues; may you have many questions that your Doc can answer for you. Forget about those that have no comprehension of what you have gone through!
Peaceful healing to you.
Red Rock