Well this is not medical advice because I am only a student as yet. However my own experience may help. I'm PAIS, my op was a long time ago - but was broadly similar to standard SRS... back then if I recall correctly, we were made to rest for about ten days in the immediate aftermath, but after that we were told that as long as we weren't straining, the more exercise and work we did the better.
I went back to work after a month, but only part time at first, but then working development laboratories (which was what I was doing at the time) didn't really involve much. About six weeks after the op I decided I needed a new patio - and was swinging a lump hammer to break up the existing concrete - which I then lifted into the skip (dumpster).
I recall that I did get more easily tired than usual, and as one of the few here who has some insight into the likely pressures of working in a healthcare environment I would say that you would probably be being rather ambitious to plan on going back to work before 6 weeks, and probably not for 8 weeks. The op does take it out of you and you will be more tired than you expect. In fact that sums up my experience really. The pain was far less than I expected, the tiredness was far worse.
So I would plan on the basis that you will have at least 6 weeks off, but warn your employer that as this is medical treatment recovery rate cant be guaranteed and be prepared to go the full 3 months if needed. Then if you feel ok at the 6 weeks go back part time for a few weeks ramping up gradually. As far as the lifting is concerned, as long as you use good techniques and don't lift beyond your capacity it should be fine.
