30 days late???

so i'm 30 days late. still haven't tooken a test because i'm scared. my bf says that's normal and girls do that all the time but this is never happened to me. my periods has been regular since last month. last month my bff and i split apart and we used to be in sync. my bf and i had unprotected sex about 20 ish days ago and ever since then i've been extremely tired and nauseous but i think i'm getting sick because my nose is runny and my head has been hurting. what do i do??