sex, plan b, bleeding

Hi I had sex 5 days ago and we used protection and I took a plan b the next day. But yesterday, I woke up with some blood on my underwear and noticed Im bleeding and I just finished my period a week ago so would this be from the plan b? or is it my period? or am I pregnant? i’ve looked it up and it said that it could be spotting from a pregnancy but at the same time i’m wearing a pad and it fills it up over night and somewhat through the day. Like I changed it 2 hours ago and my pad is moderately full. If you see this plz give me any info you know. Thank you.