I was just wondering. I started my period on Feb. 13 2009 and I had sex the next day... but I don't know if he came in me or not... I believe he did. Is it possible that I could become pregnant? Because today is the third day and my period is starting to end and it usually lasts 5 days.

It's possiable,but you won't know until 14 days after you conceive..

Lets say,he cummed in you yesterday,the sperm and your egg hatches within two days,it takes 14 days after that to conceive,and then you can take a pregnancy test.

Possible, but unlikely. You would have to be ovulating early this cycle so that one: his sperm will live long enough (they die off pretty quickly when they don't have the right environment as it is right before ovulation) and two: you will release an egg in time to be fertilized which usually doesn't happen quite this early. It can happen, but it is not the norm. Best to always use protection, at any time of your cycle, to increase the odds of avoiding an unplanned pregnancy.