What Are Gestational Diabetes?

I took a 1 hour non-fasting glucose tolerance test a few days ago and got a call back and they said I failed it. She said something like the level was supposed to be at 135 and mines was at 145. So now I have to go back and taker higher grams (100) and do a fasting 3 hour one...I read up on it a little bit and im really scared for my baby. I hope that i dont really have gestational diabetes 😣😣😣😭😭