ttc while nursing.

So my baby is going to be 9 months old on the 13th and I have been trying to get pregnant since he was a month old and no luck yet. Just kinda bummed it hasn't happened yet. I have not had a period since I have had him either. It's just weird with my other three within two months of delivery I had a period. Just wish I would get my period so I can get preg!!  Anyone have any advice??