Implantation bleeding ?

Is this inplantation bleeding or what ? I stopped taking my BC a couple days ago, my fertile week was the 6th - 12th my ovulation day was that Wednesday. (From what glow says) Or could this be from me stopping my bc? I've never had problems w spotting before when I'd stop/miss a pill. I can't remember if I had sex last week, or the week before, but Sunday, Monday & this morning I did ( it was all unprotected, no withdrawal either, except Monday)