chances of being pregnant?

so i need some help on whether or not i could possibly be pregnant. my period is seven days late and it is never late. it hasn’t been this late in two years. i’m on birth control and i have never missed a pill, but i vary within an hour of taking it each time. i had sex with my boyfriend three times about 12 days before my period which is right in the middle of ovulation right?? but those days i took my birth control. just maybe an hour later than usual. please help i’m 18 and i’m scared out of my mind. the only things i can think that would make this happen is i traveled home for christmas (only an hour flight), and i recently stopped taking iron supplements.