I care about a lot of animals more than I care about most people, and would not want them to suffer. This however doesn't keep me from eating them because I need sustenance and my body was designed to eat omnivorously.

The human body is not designed to eat animal products. See this chart:

Do you seriously think that you know better than around 200,000 years of human evolution that has designed you to be able to eat meat, as well as fruits and vegetables?

No, I think doctors and science known better. We are opportunistic omnivores, not obligate omnivores. We adapted to eat meat for survival. The western society is not only well past survival point but the consumption of animal products is damaging our health, environment and depleting resources unnecessarily. You don't have to believe me, read through this website and follow the references on it if you're still sceptic: http://www.cowspiracy.com/facts/

So you're under the assumption that because plants can't tell you that they feel pain that they don't and their life isn't as valuable as your animals are?

The comparison of plants to animals is a common one when you ran out of arguments. A lot of plants give their fruits freely without needing to damage the whole plant but let's say that the plants we kill do feel pain. Veganism is about reducing UNECESSARY suffering. We eat plants to survive while animals are enslaved and killed purely for human enjoyment.

You realize that plants are more important than animals as far as your existence is concerned because without them you would have no oxygen and die.

Yes.

By your logic you should just not eat, wither away and die.

Where did I say that? You do know you don't need animal products to be healthy? This is not a new concept.