Plan B step one question !!

So about two weeks ago my boyfriend and I had unprotected sex, he came on my thigh (we used the pull out method) he got scared that he might of accidentally got me pregnant so he bought me the step one plan B pill, we had sex on a Friday and I took it on a Monday. Now here’s the question, before anything my period is VERY irregular- and what I mean by that is that in 2020 I had my first ever period for about 3 weeks and it stopped for a whole year. When I took the pill the full week passed and I was getting “the plan B symptoms” then they calmed down abit on Saturday but Sunday night was when my uterus started to hurt a lot… but then on Tuesday or Monday I got my period for the first time in a year…now my question is..is there any way that the reason I got my period once again was causes of the pill? Cause I feel cramps and discomfort in my uterus and I’m also bleeding like I would if I were to be in my period….help-!