Failed my 3 hour glucose test..

I'm in shock and super upset that I have gestational diabetes.. I have only gained 6-8 pounds my whole pregnancy. I know that doesn't have anything tondo with how your body regulates sugar but I am feeling completely discouraged.. I take a class next weds to tell me about nutrition and I guess how to use the blood monitor. I stupidly read somewhere on the Internet that said we mom who have this while pregnant are twice as likely to have a child with autism? I don't know if that's true but now I'm totally worried... Please are there any moms out there who have gone through this and had perfectly normal children? I just need some reassurance... I may sounds crazy but I'm just freaking out right now.