Plan b?

I took plan b 5 days after unprotected sex when I was ovulating. I am 240 lbs with a bmi of approx. 36 and heard plan b doesn't work on overweight women. I'm concerned that because I took it at the end of the acceptable window/because I'm overweight I may still be pregnant? Does anyone know anything about this? Btw I don't get a regular period but I do ovulate regularly. So I can't just "wait til I get my period"