I got my AF back about 8-9 months after my son was born while I was still breastfeeding him day and night. It just started like a normal AF. It was probably normal in flow, but to me felt heavy because before having my son I had very slight AF's.

I haven't had an AF since having my daughter though because this little surprise bub snuck in before my first AF arrived, lol. I must have ovulated when she was around 4-5 months old even though I was fully breastfeeding her and my son was still breastfeeding at least 3-4 times a day.