Gestational Diabetes

So I'm 31w4d and my doctor called to let me know that I failed my glucose test so bad she isn't even sending me for the 3 hour one. I would laugh if I wasn't in such shock.... I did not expect this at all. She told me I have gestational diabetes and sending me to the specialist. I'm not scared or anything... I almost feel embarrassed. Like did I do this to myself? Was it because I have grilled cheese for dinner occasionally? I'm not an unhealthy person. I eat my veggies, I move around, I'm at a perfect weight and my mother never had GD so why did this happen? I haven't even told my husband yet. I feel so weirdly guilty