Pregnant???

so my period is never late and this month it is, it was supposed to start december 1, 2019. IT DIDN’T!!! last time i had sex was after my period in november. we didn’t use protection(it was in the moment and i was stupid) i’m on birth control but i really think i’m pregnant. the worst part is that i’m 13 and my parents will kill me if i’m pregnant. i bought a pregnancy test but i’m scared to use it. what do i do if i am pregnant? please help me!!! and i know i’m an idiot for having unprotected sex at this age but please don’t judge me, i know the mistakes i have made.