scared

my period is late by about 4-5 days. me and my boyfriend have had unprotected sex once (not even like full on because of not wanting to have a pregnancy occur). we are in high school and now i’m getting scared. for the past week or so i’ve been experiencing my normal pre-menstrual symptoms like breast tenderness. i’m just extremely nervous because i can’t really access a test without talking to my mom (which would be disastrous). for reference though my period has been 1-3 days late for the past couple months. i am still scared. any advice?