Judy, you really need to go to the Low Carb Diebetes Forum and have a good look around and a read, especially the excellent "Newbies" guide.
There are many threads in the forum, dealing specifically with ibs and Byetta. You need to ready, weigh up the information and then find the right way forward for you. I am not a doctor and do not know you, so is in no position to advice specifically.
However, for me Low Carb is 30-50 carbs a day and include eggs and bacon for breakfast with a white coffee. Lunch usually mixed salat with roast chicken or cold poached salmon. Dinner consists of at least 3 (each 50g) different vegs + meat (approx. 200g steak, pork, lamb, chicken, homemade burger etc or poached fish, like halibut, salmon, seabass, lemon sole etc.). The meat is always done on a George Forman gill and fish poached in a frying pan, but I nearly always have a spoonful or two of my own homemade dressing, especially with salat.
Snacks are for me a little chocolate (90% coaco) with a coffee in the afternoon and a digestive with a MiniBablyBell and a diet coke in the evening (I do light exercise 2 hours later).
I exercise by brisk walking at least twice a day and in total 3-5 miles a day.
This is what I have found works for me, by trying different foods and portion sizes. You need to experiment to find the right balance for your specific needs.
Best
Alice