late period

im 17 and stupid enough i had unprotected sex about a couple weeks ago, but after 5 minutes i stopped it because i realize what a mistake it was. my period is 3 days late and its never been late before, and i have no symptoms i usually get. am i just overthinking it or is there a chance i could have gotten pregnant? im too scared/have no way of getting a pregnancy test, and want a second opinion before i commit to getting one. im really scared