Negative HPT and implantation bleeding.

So according to glow AF was supposed to come on Tuesday so I took a hpt. It was a BFN. :(. But yesterday (Wednesday) I had what I believe is implantion bleeding. Yesterday was day 10 past my fertile window.. So it could be implantion bleeding correct??? I had implantion bleeding with my first baby and that time around I knew I was pregnant. I just knew. When should I take another test? Any thoughts? And baby dust please!