Is it posdible to have a normal cycle after you had unprotected sex the day you were ovulating and implantation a week before your next period is due?

Well....: If you're asking if you are pregnant now the next step is to check a home pregnancy test. If you're asking why you had an episode of irregular bleeding there are a variety of causes as this is very common. Implantation bleeding is not actually that common. It gets mentioned on the internet a lot but in real life other causes of midcycle bleeding are more common. If your pregnancy test is negative then you did not have implantation bleeding.