Hi We Did The Deed Last Dec. 28, 2016 And

Hi we did the deed last dec. 28, 2016 and we used condom and pull out method to make sure i will not get pregnant. After 3 hours of the deed i took 4 pills of nordette at around 5:35pm and took another pill at 5:30am. My problem is this, today is the 7th day after i took nordette but i still don't have withdrawal bleeding. Can i still get pregnant? Btw, i have irreg cycle and lmp was last dec 7-12, 2016. Please help. Thanks