Implantation spotting, if it happens at all, happens as the embryo implants into the uterus. This generally happens 7-12 days after ovulation. I agree with the PP, test and find out for sure! Good luck!
Once my best friend was super bummed her period came a bit early- it was borwnish and only lasted a couple days. I challenged her to test a week later since that was when she was officially *due*- sure enough- bfp! THe color can range from brownish in color, tinged pink cm, or even bright red bleeding- keep us posted!