When to retest?

Hi guys! I don’t get a period more than once every few months (I have PCOS and I’m on birth control- Lolo which can eliminate periods) and my boyfriend came in me on the 29th of August. I took a pregnancy test that was negative the 7th as my period was supposed to come the next day. I have not gotten my period yet- just brown discharge the 8th (when my period should have come). If that was implantation bleeding, can I test again now? How accurate will it be? Any advice on when to test? I feel a little off in terms of nausea but I’m not sure if it is related. Any help would truly be appreciated