Need advice with the nexplanon

I have a two month old and I have had the nexplanon place on December 4. This is my third time with it and the other times I have had normal period. This time around I was 6 days late and now I have a very light spotting(TMI I have maybe 4 or 5 drops of blood a day) . I know it can change periods or even stop then but can it happen this fast or should I pee on a stick? I need advice or something I do not want another baby with me having a two month old