TTC while breastfeeding

My daughter is almost one (on the 27th) and my husband and I are trying but not trying if you know what I mean for another baby. It's been a little over three months now of not using any birth control and I'm still not pregnant. I find myself getting very jealous of other friends or family that are pregnant. Why isn't it happening for me? Will I ever get pregnant while I'm breastfeeding?