Update... Period 12 days late BFN

I had recently posted about my period being late and being almost 5 mpp Fri, having my daughter. I was supposed to get my 3rd period after having her on the 8th of this month but so far have not gotten it. I took 3 tests and all came back neg and I am not having any symptoms of either prego or pms. Any one else have the similar thing happen shortly after having a baby?