I'd wait a day or two, then test again if AF still hasn't come. The bleeding could still be implantation, since the hpt looks for hCG, which isn't produced until implantation, with a CD10 implantation, your hCG may well still be too low to detect. If AF does arrive after all, it might be a good idea to discuss the bleeding with your GP, who could do some tests next cycle for hormones, which, as Strawberry said, could be out of balance.