Sometimes it goes away but if your family has a history of diabetes then you may end up as a type 2. You won't have to take insulin or meds as long as you watch your sugars and keep your weight down though. It's worse if you're heavy. I've always been on the extreme side of hypoglycemia and it's very hard for me to keep my sugars up as an acceptable level but already my sugar has spiking and dropping. Since almost everyone in my family is a type 1 or 2 diabetic I have to be tested in a couple of weeks. For the most part though I do just fine on a food sliding scale. If you haven't yet you should get a glucometer to test your sugar a few times a day until you get used to a certain schedule of eating and learn what types of food cause you to spike. Always go for staying power like nuts and fruits instead of candy. Foods heavy in starch can cause your sugar to spike as well.
As far as the baby goes, you may have a large one if your sugar stays high but it's not a given. However, if you have to take insulin while pregnant then you're guaranteed at least a 10 lb baby. My siblings and I were all between 10 and 12 lbs bc my mom has been on insulin since she was only 3 days old and had to up her doses during pregnancy. Having gestational diabetes does not mean your child will have it and even if you have a large baby you should still do just fine. My mom had all of us naturally with no problems. :)