Late period with Plan B

I had unprotected sex about a month ago on the first day of my period(so I couldn't have been ovulating then) My SO didn't cum at all and I took a Plan B two days later just to be safe. My period is a week late but I have white discharge and clear signs that I'm about to get my period. I'm holding off another week or so to take a pregnancy test, but has this happened with anyone else? I know Plan B can mess with your period and hormones.