Hi Mamma F.
I would talk to your OBgyn. Every pregnancy is different as you know!
I started my cycle like you later after the birth of our first child. I was not using anything while I was breast feeding. I did not use the mini pill and was pregnant again with Number 2 when Number 1 was 10 months old.
Not too big of a surprise because we had planned to try again when Baby 1 was one. After the birth of Number 2, I too started within a few weeks of the birth and I too was breastfeeding. I immediately was put on the mini pill and used it just like the regular pill the 15 months I breast feed Baby 2. I then transitioned back to the regular pill. So as you can see and probably have heard, it is not unusual for you to start earlier and yes, I would stay on the mini pill while breast feeding unless you want Baby 4! Best wishes to you and your family! :)