Period 3 months postpartum normal?

Kaitlyn

Hey guys! First time mom here. My little one is 3 months old now and we have been exclusively breast feeding since birth other then a few odd bottles I've pumped here and there. I have started what I believe is my period is this normal at 3 months postpartum and exclusively breastfeeding? Should I be worried about a drop in supply or changes in milk? Just worried my little guy isn't going to get enough. When my sister had her kids her period did not return till at least 6 months postpartum or longer. So this just wasn't something I expected so soon.