Hi Anonymous,
Same here, I was on cerazette for 9 months and in the beginnen had prolonged periods. After my body got used to it, still had monthly bleedings but they only lasted for 5-6 days (normal periods). In June I had forgotten to take 3 pills in a row and I am now also having my period for three weeks in a row. I went to the doctor to check, but nothing to worry about, since it is such a light pill, your body needs some adjusting time because of the forgotten pills (like in the beginning).
I think it is quit normal you (and I) are experiencing this. I'm hoping the bleeding will stop soon. When I started with Cerazette 9 months ago, I bled for a month in a row, and then everything turned to normal.
You could see a doctor if you are too worried about it.
(sorry for the bad English, it's not my native language)