Suggest Remedy For Missed Periods

good afernoon doc. this is kajal. am 20 yrs old. i had my last periods 2 months ago i.e. on 10th jan and i had an unprotected coitus on 16th jan but i took an i pill within 72 hrs of the intercouse. i held home pegnancy tests thrice and all were negative but i am afraid because i am not gettin the periods since then..please recommend somethin.