Is there any way it could be implantation bleeding?

mtl

My period was due on the 11th, but never came. On the 8th or 9th, I started having very light pink discharge that went on and off for a few days. The discharge stopped and still no signs of AF. I've taken 4 pregnancy tests and they've all been negative. Any chance that I just ovulated really late and the discharge was implantation bleeding?