I Had Unprotected Sex About 11 Days Ago. It Only

I had unprotected sex about 11 days ago. It only lasted about a minute and was my first time to have sex. I've got my period on the 22nd , Which is today. I was laying down and I noticed my stomach had a heartbeat kind of in the area of which a baby might be. What do I need to do? Is it possible that I might be pregnant??