Possible Plan B fail???

I had unprotected sex with my boyfriend Friday night/Saturday (May24-25) morning and took the plan B on Saturday around 2-3pm. So initially i took the plan b 12 hours later. I’m scared because i was fertile during those days and Saturday was the day before my ovulation day, it was my highest day risk of pregnancy i didn’t know. I recent just got off BC about 9+ months ago and finally got my cycle regular the last 2 months. Although i took my plan b on time is it possible for me to be pregnant because of how fertile i was?

Update May 31:

So this morning i woke up bleeding not a lot. I wouldn’t call it spotting. Should i be worried or does this mean Plan B worked?

My period is suppose to come Next Sunday or Monday (June 9-10)