Should I test again?

Ok so o have a Weiss question. I went in to my doctors office 3dpo due to UTI symptoms. So the dr ordered a pregnancy test with the urine sample I gave before prescribing me any antibiotics. The pregnancy test gave a BFN but I am thinking it was too early to tell. So you ladies think I should retest again later in the week? I am currently 6dpo. What do you ladies think?