Just to add to Lyn’s excellent advice. You may indeed be feeling pretty normal after 6 weeks in terms of everyday life, but major abdominal surgery takes a long, long time to fully heal in terms of all the muscles that are cut inside you. I was a keen hill walker before my surgery (in my case not a prostatectomy, but a nephrectomy, which is very similar in terms of muscular damage) and it took me a good six months before I was able to sustain the same level of physical exertion that I could before surgery. If your body says “Stop, you’re doing too much” then listen to what it’s telling you.
Best wishes,
Chris