Period/implantation bleeding

My period was due on the 11th I got it a day early on the 10th I bleed for 4 days (normal cycle 5) last four days I’ve had brown discharge and from this afternoon it’s going pinky brown.. so 8 days of bleeding?? I’ve had slight cramping lower abdomen but nothing to complain about but only last two days.. I was with my partner last on 25th (23days ago) April and took a negative pregnancy test 8th May period on the 10th a day early and four days of light bleeding now it’s brown.. total of 8days?? My flow is usually 3 days heavy 2 light than finished.. Is this normal after a period???? Or could I be pregnant and implant late? Either way 8days!???