Im on yaz and having breakthrough bleeding what should i do?

I began taking Yaz about two years ago as a way to help calm my acne. I felt I had gained some weight so this past summer I decided to stop taking the pill. By about september my acne had flared up again, so I decided to get back on yaz. It has worked wonderfully for my skin...However, Im about to take my 19th pill of yaz for the month and Ive had brown spotting/light bleeding for the past 7 days! I feel like its just never ending! My period is supposed to come after another 6 pills...will it still come? I'm scared because I have never really had a problem with breakthrough bleeding on the pill before and im not sure what could be causing this to happen? I take my pill everyday when i wake up, so It's always around the same time. Can anyone help me??