I was a vegetarian for many years. I got terrible cravings for meat when I was pregnant with my first child, and in my heart, I knew my cravings were telling me something. Also, My Man is an obnoxious carnivore, so it would have been difficult. I went back to some meat (not a lot) and my pregnancy nausea resolved in a matter of a day or less. Evidently I was missing something. I do believe in eating what your body tells you to.
I don't eat any dairy (with the exception of butter sometimes) as no mammal NEEDS milk after weaning (and before weaning that milk should be the milk of it's own species) and I only use eggs in baking and cooking.