Personally this time round I went back to circuit traning classes after 3 weeks. Had a normal delivery, home the same day and felt fine. Laid off ab exercises for a few more weeks, however.
First time round, however, was a bit of a shock to the system (having a baby in the house I mean, not the birth, again normal easy delivery), and felt soooo tired, but I remember I was back in the gym after about 6 weeks.
First time round they kept changing the time and date of my post natel check so I didn't bother going. This time I went to post natel check but wish I hadn't bothered as it was imo a waste of time.
I'd say jst do what you can, so long as you feel ok, but p'haps your physio is advising 3 mths beacuse of ypur spd?