Yes, you can absolutely take the i-pill to help prevent pregnancy. The i-pill contains levonorgestrel, an emergency contraceptive. It is most effective when taken as soon as possible, ideally within 72 hours of unprotected sex. Since your exposure was last night, taking it today will be highly effective. Please try not to worry; you are taking the right steps. Keep in mind that this is for emergency use and may cause mild, temporary side effects like nausea, tiredness, or slight changes in your next period. If your period is delayed by more than a week, please take a home pregnancy test just to be sure.