I also deal with it by not giving a ****. It is my body, my life, and my choice to be a vegetarian. I gotta say though, just yesterday I had the funniest response from someone who learned I was a vegetarian. I was talking to someone else in my Earth Science class and this guy overhears the conversation I was having with my friend and he just cuts in and says "You're a vegetarian?" and he just gives me the weirdest most confused look I've ever seen. Another classmate proceeded to laugh and say, "You're looking at her as though she is an alien." I just thought it was very funny. I don't get insulted, I just laugh at other people's ignorance, because I gain nothing by getting angry or insulted.
While I do my best to encourage my parents and siblings to eat a more plant based diet, I do not feel the same way about my dog. Dogs and cats have different nutritional and dietary requirements than we do. While my dog LOVES eating veggies and fruits, along with other vegetarian foods, he still eats dry dog food with meat. The reason for this is that I do not know know what foods he needs in what percentages.
I suggest getting some blood work done as well as consulting with someone who knows about animal nutrition, and by that, I do not mean a regular vet, but one with nutritional training. Regular vets get very little training/ education in regards to food. That way, you know exactly what your dog needs and if his/her food needs adjustment. By consulting someone who knows about dog food requirements then you could eventually even make your dog's food.
However, I think it is risky to change your dog's diet. Just like with humans, there are certain vitamins that we cannot survive without, such as B12 and Omega 3 which come from animal sources, but of course can be gotten from supplements. Animals, are the same, there are a few vitamins that dogs and cats need that are not readily accessible from plants. That is why I would be wary about a dog or cat on a vegetarian diet. Animals were not designed to eat a vegan or vegetarian diet. As such, I would tread carefully. http://pets.webmd.com/features/veget...diet-dogs-cats
Lastly, make sure that your dog gets more frequent check ups. While we may be able to express and feel changes in our body when something is off, they cannot.