Could this be implantation bleeding??

Af was due 2 days ago... no signs instead i have been very nauseated, dizzy, had minor headaches and cramling as well as back aches on and off for about 2 weeks now. At around noon today I started having pink spotting that was accompanied with light cramps. It came for a few hour and left... i got a bfn about 4 days ago.... could this be implantation bleeding? Could i still be carrying a baby?