What Causes Abdominal Cramps While On Mylan For Irregular Periods?

Hi, my name is XXXX. I am 28 years old. I have just recently started taking Mylan low dose birth control. It has been about 3 or 4 years since I have taken birth control. The Mylan pack that I recently started was for a few reasons, one being to help with menstrual problems and for the fact that I am getting married in one month and would otherwise be on my period on my wedding day. :-( So, my doctor prescribed the medication and advised that it was fine to go ahead and start taking it mid-cycle, which is what I wanted. I knew that was a possibility of some spotting because of this, but I have all but started my period around the same time I would have without the medicine. This is very concerning to me. I have also been taking the medication like clock work, every day at 8:30 am. :-/ ? I don t understand what s going on and haven t been able to get in touch with my doctor. I am cramping and taking midol etc. and still in a considerable amount of pain. I know I am NOT pregnant since I am not sexually active currently. Please Help if you can. :-( Thanks