What Causes Irregular Periods Ever After Taking Qlaira?

I am a 27 year old female and I have been precribed Qlaira. I am in the second month of taking the pill and I still have irregular periods. My period stopped for the first 7 days of the second month but I have had bleeding ever since. Is my body just getting use to the new pill. I have had ultrasounds and regular pap smears which indicate that everything is fine. Thanks