What was your experience with implantation bleeding?

AF was due August 16th on the 17th i thought I started but it was brown like the usual start of my AF and NEVER changed 4 days of hardly anything, only when I wiped. And very light cramping the 1st day. I usually have a very heavy flow, blood red and excruciating cramps due to endometriosis.. I haven't taken a test yet.. I don't want to be let down for the 7th time! Is this implantation bleeding?

Can you comment your experiences with implantation bleeding!?!