I don't think you had enough protein and fats. When you have a carb serving, you need to also have a protein or fat. For example, don't eat the crackers by themselves, eat cheese with them. Milk by itself is horrible for blood sugar and I would eliminate it entirely. Try unsweetened almond milk. You can pretty much drink as much as you want of it. I was also told to only eat 40 carbs for dinner. If this was one meal in one sitting, it was a lot of food. Portion size is very, very critical. If you want to bulk up your meal, take away the crackers and bread and eat more protein. A bigger piece of chicken is perfectly fine. Also, go with regular fat dressings. Ranch is perfect. Skip the bread. Wheat bread, wheat pasta, and brown rice can be deceiving. I eat a TINY portion every now and then or just go without.
It takes a little while to get the hang of this. My class was very thorough and with all the information they gave us, I had my sugars under control every time I checked within two days. Not all GD can be treated with diet alone. Make sure you keep records and within a week, if you are having trouble talk to them again.
Are you on an eating schedule? You've got to spread you daily allowance of carbs out though out the day or else yo will spike. I can send you the plan I used for that if they didn't explain it. You should be having three snacks and three meals every day. At first it's hard to do because there is a good amount of protein to eat and I was rarely hungry when it was time to eat again!
Also, something that works well is taking a 10 minute walk 1.5 hours after each meal. That helps to bring the sugars down.
GD is no fun at all, but it's temporary! Feel free to PM me if you'd like, I'd be more than happy to help more!