You did a big no, no. Sperm can live for several hours outside of the body if there was any on your penis and your girlfriend is ovulating then you have a pretty good chance of celebrating fathers day next year. If you like to go bare back then get a spermicide or have your girlfriend get on the pill or shots.
Just assume if ur not wrapped you could become a daddy . Why risk it.
Having unprotected sex is a big risk for pregnancy. The "pull out method" is not a form of birth control because there is sperm in pre-ejaculation. If you are not ready to be a dad, use a condom. If her period is late, ask her to take a home pregnancy test.