You need to have sex around the time of ovulation. We can't tell you if you're ovulating or not. Whereabouts are you in your cycle?
Women ovulate around mid cycle, then they get their period about 12-18 day after this ovulation. So to conceive you need to be having sex every other day until ovulation, and again for a few days after to ensure you've 'covered all your bases'. All you can is wait until your next period is due, and if it doesn't show then take a pregnancy test.
Only if you ovulate within a day or two.