Condom broke 1 day before ovulation, took a plan b, then had light brown spotting a week before my period was due and it lasted for an entire week before I finally got my period (it was on time)

A little over a week ago (3 weeks after my last period) I was feeling very ill so I took a pregnancy test and it came out negative. However, now I am 31 days into my cycle but I normally get my period on days 28-30. Has plan b ever caused this for anyone or should I be concerned?