could i be pregnant??

Destiny
Hello!! I've been breastfeeding for 13 months, we have been TTC for about 3-4 months seriously and before that we weren't taking precautions anyways! No luck though, I heard breastfeeding can be it's own birth control? But I didn't think it would keep me from getting pregnant at all, kinda discouraging. We have been weaning my daughter from breastfeeding, she feeds at night only now. Anyways, this month I ended my period around thanksgiving, my periods are always off the walls so I don't usually track very well, i'm always "late". This past week i've been crazy emotional and i've cried more than once, I don't usually cry. I started feeling nauseous yesterday and today as well. I took 2 tests and both came out a BFN. Is it possible I could still be pregnant?