Menstrual Cycles & Toprol

I have been on Toprol since 2003 & have had ovarian cysts for many years prior to that. For a long time I was on birth control pills to regulate my cycle & keep the cysts from coming back. It seemed to be working, but I had to stop them for awhile because I had a lump in my breast at age 31. The OB/GYN wanted me off of estrogen then for awhile until the lump was investigated or went away. I was off of those then for about 2 years. I was put on Metformin then for the PCOS as well as the diabetes that I developed from the PCOS not being under control for years before being diagnosed. With being on the Metformin, my cycles were normal for about a year & then they started getting strange again. All of a sudden they completely stopped. I am only 33 now & all the blood work says that everything is normal. I was just wondering if this could somehow be related to my taking Toprol. Has anyone else had this kind of problem or is it just me & my body?