I'm sixteen, and I got my first period just before I turned twelve. For the past few years, my periods have been for the most part regular. This year, I noticed that my periods kept getting farther and farther apart. They would still come every month, but my cycle would go from thirty days to thirty-three, to thirty-five. Two months ago, I missed a period after not missing one for a long time. I got my period last month, but this month I haven't gotten my period and it's over fifteen days late. I am overweight, about 250 pounds and 5'6" and I'm wondering if this has anything to do with it. I have always been overweight, so it's not like I had any drastic weight gain. Over the past year though, I did gain about 20 lbs. I have also recently been experiencing some vertigo, and I also have developed severe stretch marks on my stomach. I always had them on my sides, but they got significantly worse this year. I'm wondering if these symptoms are related at all. Is it my weight that is causing my period to become irregular, or is it something different such as PCOS? I'm a virgin, so I know that there is no way I can be pregnant. Any help would be greatly appreciated. Thank you!