Implantation bleeding

[Babybmam1234]

Hi ladies, iv always had a regular period just a normal 6 days. This month my period started on time, with no cramps! That’s not normal for me as I normally get really bad cramping within a few days of my period, I felt this very heavy sensation down below hours before my period actually started, it was just a normal day of my first day of coming on, the next day there was nothing on the pad just when I wiped down below, and this continued for 3 days, the first day of my period was like a dark red and the next few days it was pink, iv done a test and got a bfn. Any ideas or anyone been through something similar? Thanks