plus size and Gestational diabetes

Hello, here's a little back story from me. My son was born sleeping last September. I had gestational diabetes and am having to check early this time. My Dr refused a c section even if he was measuring a whopping 8 lbs at 36 weeks. He swore he would flip, but because of my son size, he tore the placenta a bit when he tried. This time, I have more anxiety and am so afraid it'll be an issue again. But I have talked to women my size and they didn't have GD at all. I keep being told it's because of my weight, but I'm not sure. here is my question: Are you heavy and didn't/don't have gestational diabetes?