So I am on lo loestrin which is a birth control pill. This is my second month on it. I'm on the…

So I am on lo loestrin which is a birth control pill. This is my second month on it. I'm on the third week of the pack and have had my period for about a week now. Wtf? The same thing happened last month. Do you think I need to give it a few more months to even out or should I call the doctor and switch now?