Could I be pregnant again?

Baby is 3 months old now. I nurse her each feeding and top her off with formula because I underproduce. I am on the mini pill, had sex 10 days ago. My period hasn’t come back postpartum yet. Yesterday and today baby has suddenly become fussier when nursing and seems as if my supply has dropped just a little, she’s demanding more formula than usual. Now out of nowhere tonight waves of nausea hit me, feels similar to morning sickness to the point it entered my head omg could I be pregnant?