Hi My Partner Nd I Had Unprotected Sex Last Apr

Hi my partner nd i had unprotected sex last apr 27 11pm. He did not cum me inside but im afraid of pre cum. So i took 1st nordette ecp dose (4pills) apr 28 11am then second dose 11pm same day. Last menstruation period was apr 16. No side effects since this is my fourth time using nordette as ecp. I first used it last 2yrs. It has been 13 days and still no withdrawal bleeding. Does this mean nordette lost its effectivity or what? Pls help thanks