Is Pregnancy Possible Despite Taking Oral Contraceptive?

Hello sir Em 23 I had unprotected sex with my boyfriend on Sunday nite again on Monday and Tuesday Its been 4 times in total but he didnot cum inside of me . den on Wednesday I had around 1 O clock in noon I took a pregnancy test and it showed purple line on C which is negative and I had a unwanted 72 pill as dis was a first time experience wan to know hope we r on safe side plz suggest doctor . I don t wanna gt pregnant