Between the Diabeties and the pregnancy, I would be very very cautious of making any big changes in diet, especially without medical monitoring and help.
However, you could make some changes to eat less meat.
Being a vegetarian usually means that you don't eat any form of animal flesh, that includes chicken and fish. It also usually includes not eating the byproducts from slaughter, like Rennet and Pepsin, (Often used in making cheeses ). Some take it a step further, and don't eat any animal products, such as dairy, milk, cheese, and eggs. This is refered to being "vegan".
(As a side note, Rennet and Pepsin are enzymes produced in the stomachs of animals, Rennet is from young milk drinking mammals.) It is recovered from the animal during butchering.)
Anyway, for the protien portion of your diabetic diet, following a vegetarian diet, you will be able to make choices that are still high in protien. Beans and lentils for example have both carbs and protien. Learning how to prepare and cook Tofu will help. While not vegan, protien powders are very healthy (they usually contain whey) Milk is generally 1/2 carb 1/2 protien.
Basically, if you are serious about going vegetarian, I think it would be best to get a good vegetarian cook book, (And perhaps a good diabetic one too) and change a few meals a week, and as you find foods you can live with, then slowly cut out the meat. Don't make the mistake though of substituting all the red meat you do eat now for chicken or fish, this is very misguided and not really healthy.
Some things may take aquiring a taste, (most guinea pigs don't like Cilantro the first time they are given some, but they learn to love it!) . Once you are comfortable and healthy on a vegetarian diet, then you can look into if your health / lifestyle will allow you to go vegan or not.
