You might find brown rice is a good thing to eat to fill you up a bit – brown basmati is best. I try not to eat it every day but I have some every two to three days and it doesn’t seem to cause any problems. You could probably eat it more often than that if you found it helpful.
I have a recipe book by Patrick Holford which is about eating for pregnancy (sorry, I forget the title). He also does loads of other low GL diet recipe books. A lot of the recipes would be suitable for at least stage 3 of this diet. You might find some good ideas in there – and even if you don’t manage to keep to the strict diet, eating low GL food (sweet potatoes and the like) has got to be better than eating pizza.
Good luck – hope the pregnancy goes well.