My period started on January 22, 2018 and im pregnant. My boyfriend doesn't think its his. When was my conception date

Hello. Thank you for posting.

This is something you can estimate for yourself, as there is no way we can know. Day one is the first day of the menstrual period and the last day is the day before the next period begins. Ovulation happens about two weeks before the next expected period. So, if your average menstrual cycle is 28 days, you likely ovulate around day 14. This can vary. If you have unprotected sex during your fertile window—four days before you ovulate, the day you ovulate, or the day after—you are naturally more likely to get pregnant.

Helena