Hi, I Have Been On Birth Control For 2 Years

Hi, I have been on birth control for 2 years now. And my period usually lasts from Tuesday-Saturday or Sunday. Yesterday I started my new pack of birth control and today, I realized that my period is still going. It's never happened before so I'm a little freaked out. Tuesday night I accidentally wore a tampon for 9 hours. Would that have anything to do with why it's still going?