Hello Dr. In Nov, My Period Was On 13 Nov.

Hello dr. In nov, my period was on 13 nov. In dec was on 12 dec. I've taken postinor 2 on 4 dec and the second pill should be taken 12 hours later but i took it late 3 hours. And on that 12 dec till 15 dec my period was light and the color was red dark or dark maroon from the first day of period. The color was like a few days before the last period. After 1 or 2 weeks later, my stomach ache so much and it last 2 or 3 weeks later. And i always feel tired until i have done the urine test. My next period should be due on 9 jan and still not come till today (19 jan). On 14 i have taken pregnancy test by urine test and the result is negative but still my period did not come. And on 16 jan i took the urine test again and the result still negative. Today, i feel like im having a period cramp but when i go to toilet still my period not come. I want to know does the postinor 2 effect my menstruation? Why does my period still not come?