Implantation bleeding or idk?

Cindy

Hi ladies!! So my last period was june 20th-25th and my periods are always the same. I didnt get my period in july and on August 1st i had some dark brown discharge with some blood come out for 2 days. It was so little i only needed 1 panty liner the whole day. August 3rd it completely stopped and i still havent gotten a period. I took 3 hpts and all negative but still no period. What could it be? IB? AF?