I've been a lacto-ovo-vegetarian for 11 years this January.

I strongly disagree with Mitch on this. Becoming a vegetarian isn't hard - if you have the discipline to meditate each morning, I'm sure this won't be a big issue for you. In my experience those who "break" do so because they choose to, not because they lack willpower. I got cravings for a few years, but since I turned 20 or so the thought of meat actually makes me feel queasy. It would take considerable effort for me to go back to eating it regularly.

I recommend that you experiment to find what's right for you. Choose a diet and see how you feel at the end of a month; if you don't like it, make some changes. I don't know how diabetes will affect your choices, but I imagine full veganism would be a challenge. If it helps, keep in mind there's nothing wrong with easing into it - you can start by cutting out red meat, then poultry, etc.

There really is no wrong way to do it as long as you stay healthy. Watch your iron, protein, and B-vitamins and you should be fine.