Depending upon what you mean by saying consciousness is "made up," I might agree with you... or I might completely disagree with you. Our concept of consciousness is a fabrication, but as Descartes showed us centuries ago, we cannot doubt that we exist - or more properly, I cannot doubt that I exist. The nature of that consciousness is given, it was given to me, and it's all I've ever known.
consciousness and self-consciousness are about the same thing under the proper definition.
I think there's enough wiggle room to seperate the two, but they are highly related - and the difference between the two may just be a language to express consciousness.
because most of the animals we eat are not, by the proper scientific definition of the term, "conscious".
But there isn't any science behind that claim. This is an assumption, one that's rarely been terribly challenged by peole - and when it is challenged, it usually shows itself to be a falsehood.
All the reasoning we use to apply unconsciousness to animals can be equally applied to humans, if using the right perspective. We are not nearly as free as we usually like to think we are, and we are a creature of instinct as much as any animal. If you'd like an interesting book on the matter,
I'd suggest The Animal that Therefor I Am by Jacques Derrida. It's a little weird (pretty quickly he's talking about a cat looking at him naked), but he does a good job of tearing apart the false dichotomy, where man is something other than nature, and somehow special, unique or holding some traits most animals don't have.
As a side note, ever hear about that autistic girl who helped ranchers develop better methods of corralling cows? She got "in the mindset" of a cow, looking through the world as if she was a cow, and suggested adjustments to the system that worked. If humans can imagine themselves, correctly, in a cows shoes, why assume that cows are completely unconscious, or aware - especially when they show signs of individuality?