Hello, If you have regular 28-30 day cycles, unsafe period is around mid-cycle. Intercourse during the safe period has very little risk of conception. Emergency contraceptives contain high levels of hormone and thus create hormonal disturbance and lead to breakthrough bleeds and irregular menstruation. You may also expect your normal menstrual period to be delayed by a week or two. In the current scenario, you should see a specialist for further evaluation if you do not see your next cycle even after ten days after it is due. Hope this helps.