confused

so yeaa, my boyfriend and i had sex earlier this month, like the 2nd of May. he actually cum inside me bcoz we're trying to have a baby. after 4 days, i took a pregnancy test and it showed negative. 3 days before my period he cum again inside me now im 8 days late for my period and as i took the pregnancy test, it showed positive already. now im confused if Im pregnant for 3 weeks now or is it still a week?