Hello! It's been three months since childbirth, after two months I sta…

Hello! It's been three months since childbirth, after two months I started my period, I thought they would come one day and then they came for one day and there was none. After a week they came again for one day and there was none. I had an ultrasound done, they said everything is normal. Two days ago they came again and another day for one day, even for half a day and there was none. What does this mean? ??‍♀️ This is the first time I have experienced this. I am breastfeeding and giving formula.