It's perfectly normal to have bleeding after birth, whether surgical or vaginal. I had one of each, and both times I bled for maybe 6 weeks before it had tapered to nothing. I actually haven't stopped breastfeeding since the first birth, so I couldn't speak to your experience, but I didn't have periods until 13 and 14 months, respectively. The first time they were regular when they came back, this time not so much. You probably don't have anything to worry about, but I've done pg tests sometimes just to reassure myself.