What Could Continuous Bleeding While Under Treatment For PCOS Indicate?

I'm a 16 and a half year old teenage girl. I was recently diagnosed with Polycystic Ovarion Syndrome and put on birth control pills. Only halfway through my cycle of pills, I unexpectedly got my period. It's the normal flow, but I've had it for nearly 12 days now. I went to emergency a week ago because I was experiencing sharp abdominal pains. I have never had menstrual cramps before and these pains were around my belly button, therefore not cramps. They sent me home with no diagnosis after checking for bladder infection. The pain went away but my period is still going strong. What should I do?