With both of my children, I got my period one time during the breastfeeding period, up to a year old. After that, i did get my period but they were weaning, up to a year and a half old. I had questions on that as well. It is normal, especially in the beginning, when your body is adjusting to nursing, and first figuring out how much to make. With my first child, I got my period once, and then not again. I actually thought I was pregnant again due to this, but it was jsut that my body was still in the adjustment period.
If you have any more concerns regarding this, you should talk to your doctor,but keep in mind that every woman is different. I hope this helped.