missed period

Gabby
i missed my period. it usually comes sometime around the 20th and it hasn't come. i am sexually active but my boyfriend always where's a condom and he always pulls out before he finishes. the condom has never broken either. i don't understand why i missed my period though i have zero symptoms of being pregnant or getting my period. could it just be a missed period or do people think i'm pregnant??also if it helps i had sex 2 weeks ago protected! 
update: i took two pregnancy test and they both came back negative. but the test said that they were supposed to be taken 5 days before missed period. is it still true that i'm not pregnant even though they said that??