Is home pregnancy test accurate or should i retake it?

Hi there, I hd sex bt my husband dint ejaculate inside me but we are not sure..however I tuk I-pill d 2nd day aftr sex n it's been almst 16-17 days I hvnt got my periods..today that is on d 16th day I tuk pregnancy test n it came negative but I tuk d test aftr having brkfst in d mrng..is it accurate or do I need to tk a retest??