How fertile are you after pregnancy?

Rebecca

Had what I think is my first period on April 1st 3 months postpartum. I had sex April 7th the condom broke I got scared and took a plan b pill for the first time in my life on the 8th. I'm still terrified at the possibility of being pregnant. I've been slightly crampy the last couple of days I hopenits just the plan b pill doing its thing