A bit worried

Me and my Boyfriend been having sex since my birthday which is the 28 of January. I do not have any pills. We always do the pull out method...On April 12 I took a Plan B pill today is April 16 I'm on my period but I'm not sure it's the real thing because it has not been 5 days I'm not sure if I'm good or not. Do I have to wait to get off my "period" to see is I'm pragnet?