Bleeding after the Pill.

My boyfriend and I had a little fun last weekend resulting in me having to take plan b… I had just finished my period the day before but still wanted to take one just in case. It was my first time taking it and I’ve felt okay up until today. During another round of fun I noticed I was bleeding which never happens… I wanted to come on here for some advice and to see if this may just be spotting after taking the pill or if anyone has had this happen to them. Thanks y’all ❤️