Hai, How do you your ovulation? Calculative? Not possible. Only repeated ultrasound
examinations and hormonal
monitoring only able to tell the exact date of ovulation. Do you mean to say 1 st day of your menstrual cycle. Then is is not possible for you to get pregnant. Even if you know exactly your ouvultory date, having sex 3 days prior to ovulation not possible to get pregnant. So don't worry and get checked by your doctor.