Vegetarians basically don't eat meat. No beef, no pork, no chicken, no fish etc. but they can use various animal products, like eggs, milk, honey. Sometimes used together with the describing word, like lacto-vegetarians use milk products, lacto-ovo-vegetarians use milk and eggs. But vegetarianism isn't as popular as it used to be, as veganism is on the rise.

Vegans don't use anything animal based. No meat, no eggs, no milk, no honey, no leather, no wool.. basically nothing which is made from animals or comes from animals.

I'm not a vegan or vegetarian myself, but still.. not sure if it'll help your health, but going to vegetarian and still eating milk and eggs could do good for you. It usually helps many people to feel better, but still getting B12 from animal products. Vegan diet requires often more planning to get a balanced diet.