where's my second period?

11 weeks since given birth, had my little girl 16th November had my normal blood flow afterwards and my first  period on 26th December ,and that lasted 7 days I'm now awaiting for my second period which I haven't got? I'm not breastfeeding and I've took endless of test, I got Evap lines and negitives .. I'm really confused as to what's happening with my body:/