Late period

please tell me i’m not pregnant because i am panicking right now .. the last time i had sex was january 24th, no condom but i know that he didn’t nut in me . my period usually comes on the 6th or the 7th and now i’m 3 days late, i had brown discharge in my panties on the 6th which is a sign of early pregnancy or period i coming. i have cramps and i took a pregnancy test which came out negative. has anyone ever experienced this or something similar? if so can you please give me some advice i’m so scared.