Help thanks

Hi im really confused my last period was aug. 3 i didnt have a period in sept. And ive taken like 5 hpt all negative i took another one last night also negative and and night i started to cramp for a while then it went away and i woke up this morning to dark brown bleeding very light i used a pad but the bleeding wasnt enough to change it all day i have been feeling light cramping during the day but not my normal period cramping also while im having this bleeding their are no blood clots only light bleeding could this be my period or is this implantation bleeding? Also before i forget i had an hsg done aug. 7