Heavy bleeding 7 days after plan b

I had unprotected sex on Oct 29 and I took the morning after pill the next morning, and it was 14 days since I first had my period. I started to have heavy bleeding 7 days after I took plan B (nov 5) and i don't know if this is the side effect of the pill or did my period came a week earlier. I read online how people got spotting and brownish bleeding a week after they took the pill, so I am confused as to whether or not this is my period or just a side effect.