Why do I still have a period while taking Belara?

Hi, For some time I have been taking Bellara birth control pills - not for the preservation of contraception, but because of persistent and painful months. They were prescribed by the Gynecologist. On Wednesday, I finished the second pack and started a 7-day break. At that time - on Wednesday - the previous period ended. Yesterday, despite the break, there were re-bleeding and today came another, dark and slightly painful period. I have purchased another package, but I do not know whether to start the next package or go with it to the gynecologist at the end of this period. I must mention that such dark periods happened before, but very rarely, and during the examinations the doctor did not notice anything strange. The first time I took this drug happened to me this situation and I do not hide I am scared. I ask for advice. Best regards