What Could Cause Delay In Periods After Taking Xamic MF?

i had a foreplay with my fiance on feb. 28 and the time of foreplay our dress were on...it was my 6th day of period and after this i got worried that i might get pregnant so that i took an i-pill on 2nd of march after 7 days that is on 9th of march i bled and it continued for 9 days that is till 11th of march on 10th i visited to a gynecologist for query of heavy bleeding and she recommended me xamic MF for 3 days 6 doses... and i stopped my bleeding by this..now my periods should be on 23rd of march but it did not came till now m so worried....plzz help me....