Plan B fake periods?

Hey girls, so I was on the pill and had unprotected sex with my boy friend about a month into my pack. I was just about to start my sugar pills on the day the condom broke on us. I got really scared, so I took plan b. My obgyn told me to stop my bc till my next period comes, but I heard that plan b gives you fake periods so I don't know when to take it. My period was ten days late and I started bleeding today (took plan b on the 31st), should I start my next bc today? Or is it just the bleeding effect of plan b?