I had sex with this girl on the 8th of december (her period usually comes on 21st and after). We used protection and I even ejaculated outside. I still gave her a plan b though just to be safe. Her period came about 8 days later but 4-5 days earlier than usual. Now it is january and she got some small drops of blood and ovaries pain, could this be implantation? Or is it the way the plan-b disrupted her normal cycle?