missing a a pill on the 2nd or 3rd day after my period

i need help please.... i had my period 20 of December and i started to take my pill on the 24th. but i forgot to take one pill im not sure if its the second or the third pill. and i had contact with my bf on the 3rd day. im sure that i took a pill the night i had sex but i didnt that i am missing a pill till the fourth day. i am not sure if i took the pill of the second day on my third day coz when i check my pill first and second pill was empty but i am sure that i took the pill the day i had sex and it was monday. when i came to know that i am missing a pill i took 2 pills on the fourth day. is there any chance that i get pregnant because of this. i am still on my first week after my period... please help