6 weeks postpartum cramps?

I’m 6 weeks postpartum tomorrow and have been cramping on and off for a week. Nothing major, but feels like a mild/moderate period. I wouldn’t worry, but I hadn’t been having them then hubby and I had unprotected sex at 4 1/2 week PP (midwife gave us the okay). So now I’m wondering if it’s another pregnancy. Anyone else with cramps this late into PP? Not bleeding (had some small spotting at 5 weeks)