How much has to go in you to get pregnant? We used a condom and I feel like a little was on the outside of if. I also had my period 2 days ago.. Should I be worried?

Yeah you need to worry... it only takes ONE.. and its microscopic... there were MILLIONS in that condom.

And even if the condom was used correctly... they are only about 80% effective... based on what you describe.. it wasn't used correctly so that number goes WAY down.

You need to take a class in human reproduction if you are going to be playing these sorts of games and NOT expect to get pregnant.