Could I be pregnant? Should I take a pregnancy test anyway?

If he ejaculated in you even just a little then yes it is possible that you could pregnant however it is unlikely. With each time a boy ejaculates into a girl there is only roughly a 5% chance the girl will get pregnant. But to be on the safe side you should take a pregnancy test and if you are pregnant and are unable to care for the baby they you should just get an abortion.