Hi TLP
I know this comes late but hopefully we can help you out a bit. If eating meat bothers you, you don't have to eat it. You also don't have to put up with family and friends having a lack of respect for your choice. If they have genuine questions, answer them politely. If they are bugging you just to see you get upset, ask them to respect your choice and change the subject.
Gelatine is made of the connective tissue of animals (bone, skin and offcuts) that is boiled down to produce a powder or sheet of collagen that can be dissolved and will set when chilled. There are vegetarian substitutes for gelatine, such as agar and carageen (made from seaweed) and pectin (from fruit, like the stuff that makes jam set). You can get vegetarian lollies and things, you just have to look at the ingredients.
There are many types of vegetarians, and you have to decide what you are personally comfortable with. (Just a note, I don't personally think anyone can call themselves vegetarian and eat meat at all, so no chicken/fish even though some people would consider that 'vegetarian'). Ovo-lacto vegetarians will eat dairy products and eggs but no meat. If you don't eat eggs but will eat dairy, you're lacto-vegetarian, the opposite would be ovo-vegetarian. Vegans do not eat any animal products at all, so no eggs or dairy and no animal by-products, such as honey, gelatine, whey, casein and some food colouring.
People might choose not to eat eggs or dairy because of the way they are produced. Egg-laying hens are generally kept in cramped, unhealthy conditions and are killed when they stop laying eggs. Dairy cows are artificially inseminated, give birth to a calf which is taken away and are kept lactating by constant milking. The calf is usually killed for veal or might be kept as another dairy cow to continue the process.
B-vitamins can be found in some plant products, such as vegemite, and most soy milks are fortified with B12. Most rice and nut milks are not. For convenience I take a multivitamin with B-complex and make sure it has B-12. If you were anemic in the past, you need to know whether it was because you had low iron or low folate or B12 or something else entirely and address the problem from there. If you are concerned you can talk to a sympathetic doctor or get a consultation from a nutrition specialist.
Protein is everywhere. You get most of your protein from beans, nuts and grains (and eggs or dairy if you choose to eat it). If you can worried about not getting enough, you can also make protein shakes! There are several types of protein, some based on whey (dairy) and others based on soy, peas or rice. You can get Nature's Way brand soy protein at coles or bilo I think, and it's not bad at all. It's easy to shake it up with some soy milk or put it in the blender with soy milk, soy icecream and frozen berries for a really yummy shake.
Being vegetarian or vegan is a personal choice. You have to look at what makes you comfortable, be willing to learn a bit about nutrition and enjoy finding new ways to cook. It is totally possible to be very healthy practicing a vegetarian or vegan diet!