Anyone Help!.

helloo... just dont know what to do. I had sex last 1/14/18 and my first day of my last period was 12/15/17 supposed to my menstration would be last 1/15-19/17 but still no period. by the way after we had sex immediately took pills up till now is it possible that all this symptoms im feeling right now like breast tenderness, nausea abdominal cramps are the side effects of the pill. i already tried pregnancy test and all are negatives. plsss. help.