im REALLY late

Im 13 days late and im starting to really freak out. I know its been almost 2 months since the last time i had sex. And last month i got my period. But this month i spotted once and nothing since. My mom dosnt know im not a virgin and i would hate to have to break the news that im pregnant at 18 going into my senior year of high school. Please i need help i know it could be stress but its never been this late before and what stressing me out the most is my period being late.