Suggest Remedy For Delay In Periods

Hi...me and my galfrnd had sex on 1st jan 2011. we used condom but dat broke in during intercourse. within 12 hrs she took I-pill. after 4 days her vaginal started bleeding which was continue for 3 days, den stopped. Normally usually her periods comes during last week of every month but till now she didnt get it...so Im little worried. should we consider the abnormal bleeding also.