Pregnancy test

Took a pregnancy test About 21 days after ovulation, (had sex 3 days after ovulation without a condom for about 10-20 seconds) so 18 days after sex just to make sure. Came back negative right away right after I peed, gave it some time of course still negative. This is also about 4 days after the end of my period it was really weird because of my stress so yes I still took one, but is it accurate because of all the timings the brand was ept.