What Causes Delay In Period After Sex?

hi ,i had sex with my boyfriend, but we are confirm that sperm are not inserted into vegina. but my period date will not coming so we are getting afraid, and therefore we again got sex and then i use i-pill. but after 4 day i do not got periods till now. i feel symptoms of period daily but my periods is not started.please help me how can i get me periods come faster. last time my end date was 3 july.