I have been on the pill for three months ,coming off Depo, I missed a few pills this package and the week after the sugar pill week I started spotting like a light period and cramping,still going on for about a 5 days. Could it be implantation?

Most women don't notice implantation, but if you do, 5 days is too long. Spotting during implantation would most likely only last a day or less.