Period 12 days early after missing a pill?

I recently missed a pill (Friday) then took 2 on Saturday. I had sex on Sunday morning however my partner didn’t cum in me. On Monday morning I woke up and it seemed I had started my period but it’s not meant to come for another 12 days. I’m not sure if this is normal but i’m not quite sure what to do. I am considering taking a morning after pill but what is the point if I am on my period. Can someone please help and tell my what you think the best thing to do is, or if this is normal.