What Causes Delayed Period Inspite Of Being On Exluton?

I was exclusively breastfeeding and pumping breastmilk when I started taking Exluton Contraceptive, so I haven't had my period when I started taking Exluton due to breastfeeding. But now I stopped breastfeeding for 2 months already and I am on my 3rd pack of Exluton but I still haven't have my period until now. I'm afraid I may be pregnant, but I haven't checked. Is that possible? Or only because my period is delayed? When will I start my regular period? By the way, I gave birth last August 2, 2014.