Metformin and birth control.

Hello ladies! So my Dr perscribed me metformin for pcos and my prediabetes. He also perscribed me birthcontrol. I take 2, 500 mg of metformin every day and my birthcontrol as well. Before i started my BC and metformin i didnt have a period for about 6 months due to pcos. So 3 days into taking metformin and birthcontrol i started my period. It lasted 10 days. Well im almost to the end of my BC pack and im thinking will i started my period again? Did the metformin cause me to start my period the first time? Any help would be greatly appreciated. Also i do have an appointment set up with my Dr in 2 weeks. Im just anxious to hear anything right now! Thankyou so much!