Plan b worked?

Didn’t get a period in August, but kept testing and negative. Didn’t have sex for that month.

Had sex with a condom in September. Took a plan b cause I was paranoid the condom unrolled. My bf always pulls out before he finishes, regardless if he’s wearing a condom.

I got a really heavy period 5 days after plan b (which I assume is because I missed period in August).

Am I good? Not pregnant?