What Causes Delay In Periods?

Q : I had taken unwanted 72 pill five days before. I had unprotected sex 8 days ago ,befor 2 days of my periods date. aftr 70 hurs of sex i took 2 pill togather of unwanted pragnancy .nw i am wating for my periods .y im not having priods still .Do i still have chances of getting pregnant Age - 26 Height - 5 ft 2 inches .