My last period was August 19-24 and I am pretty sure I ovulated on 9/8. I had VERY light spotting on August 21st and nothing since then. My periods are usually 35 days apart so I am about 2 days late but the hpt I took today was neg :/ any chance it could have been implantation that I experienced on 9/8 or would that be too late (it was 2 days before my expected period).