The chances of you getting pregnant are very small because you had sex on a day which is not considered a fertile day in the menstrual cycle. The fertile days are the days around ovulation. Ovulation usually occurs about 14 days before your next period comes. For most women with a 28 day cycle, ovulation happens in the middle of the cycle. The first 7 days of the menstrual cycle are usually the days of menstruation and are considered safe days for having unprotected sex... but only if your cycle is 21 days or longer. In the case that a woman's menstrual period if shorter than 21 days, she will most likely ovulate 7 days after menstruation begins.