Yes, it is quite common for the i-pill (emergency contraceptive) to temporarily disrupt your menstrual cycle. Because it contains a high dose of hormones, it can cause your next period to be heavier, more painful, or last longer than usual, sometimes for a week or more. While this is generally a normal response as your body adjusts, please take care of yourself. If the very heavy bleeding persists beyond a week, or is accompanied by severe pain or dizziness, please consult a healthcare professional just to be safe.