There is no way to know you are pregnant just a day after having sex. The pull-out method does not always work, but this doesn't necessarily mean you are pregnant. Wait for a few weeks before taking a pregnancy test.

In the mean time, I suggest using protection in the form of condoms and birth control if you are worried about getting pregnant. Better to be safe than to worry for weeks at a time about whether or not you're pregnant.

Best of luck!