Pregnancy is possible every time you have sex, but naturally, if you do not use protection, then yes, your chances of being pregnant are much higher. The pull out method does not really count as a form of birth control since pre-ejaculate can cause pregnancy just as easily as ejaculate. So pulling out does not actually do much as far as protecting you from pregnancy goes.
In the future, if you want to avoid pregnancy, you will have to use a real method of birth control. In the meantime, a pregnancy test is the only way to know for sure.