What Causes Vaginal Bleeding After Starting New Pack Of Reclipsen Pills?

Hi there my name is Raquel Vaske I am recetly on Reclipsen started this back in June of 2014, i had recently had my period march 9 and ended march 11, i take my pills every morning same time around 9:30 and never miss a pill do to not wanting to become pregnant, yesterday I started a new pack around 3:00 pm I started bleeding again, the bleeding stopped this am, confused on what is going on, some others said it could be break thru or stress but I never have expierenced this before.