Jeri, is there two things going on at the same time? Like the overeating and then the fainting? Seems like she faints when excited, so could that be the heart area that's in question? I had a dog one time that was constantly starving no matter how much I gave her. She could eat till she vomited and then eat again. I don't think she had the sensation in her tummy telling her it was full.
I sure hope the little munch comes out of this just fine. Can't wait to meet this little piglet!