I had gestational diabetes that didn't test positive until week 30 and fruit...oh how I craved it...was a no no. Once a week i'd rebel and have 2 banana's! Basically just read labels to see what the carb count is in grams. You don't have gestational diabetes (yaaaayyyy!) but here's what I had to limit.
I could have 30 grams of carbs for breakfast, 15 for am/pm snacks, and 45 grams for lunch and then dinner. The key was fiber. If I got a whole grain bread that was 19 grams carb and 2 grams fiber, I was allowed to consider it 17 carbs...believe me I looked for fiber just to be allowed 2 slices of bread! Rice...well, 1/2 cup is nearly 45 grams in carbs so I had to stay away from that, as well as any kind of pasta.
They said I could have as much protein as I wanted but fruits, beans, and some veggies (like corn and carrots) were not so good unless in small quantities. Milk was practically off limits and juice was forbidden! Geesh I was so glad my diabetes went away after I had my son!
The diabetes specialist I consulted with said vegitarians had a really difficult time with the diabetes diet because there are lots of carbs in thing you'd think are super healthy...they are healthy, just not if blood sugar levels are a problem.
You probably don't have to be as rigid as I had to be, but as the third trimester progresses blood sugar regulation becomes especially difficult. Just make sure you eat something every 2 hours and think protein and fat (yup, fat...butter is your friend for like the first time ever!) And you should be fine.
Again, I know you don't have to be as strict as I was but thought this general information might be helpful. Also, google 'carb counts and food' and you'll find everything you need to know what has carbs and how much.
There are tons of recipes on-line too.
Congratulations on your pregnancy and don't worry too much if possible...I was insulin dependent 4 times per day and my son was born super healthy:)