Just found out I have Gestational diabetes

So I failed my one hour test with the sugar drink. I had to go back and do a 2 hour test and got the results that my sugar is still high. My doctor is referring me to a dietician or nutritionist I can't remember which she said I'm still in shock I asked a few questions but the receptionist didn't answer everything. Instead made me an appt to see my ob/gyn next week.

With my first child I didn't have this. Now I have it. I feel like did I do something to cause this? I'm worried what this means for my child, what will happen to him. Or me?

What should I eat/snack on? I have no menu or meal prep expirence for a specific diet. Ugh I'm just so overwhelmed don't know where to start.

If anyone has had this please please help me understand what is going on?