Yaz and hormone levels

I have been on Yaz for eight months and absolutely loved it at first...about three months ago, my boyfriend and i broke up and i had a full blown period when i wasn't supposed to.....I just figured it was from stress. But for the last 5 weeks, I have had two full blown periods that lasted four days each and spotting every week to the point that I have to wear a tampon just so i don't ruin any more underwear...ive heard this could be from stress or weird hormone levels, but its just weird that i did so well on it for the first seven months and now this???? whats going on??