My cat does the same thing, if she is wanting attention and doesn't get it she will just walk up to me and bite me and run. Especially when I was on the phone (I had a boyfriend in Canada and we would talk for 3-4 hours at a time). I read a book by this animal psychologist type person and...
My cat used to barf a lot- I don't know what caused it, he would usually not throw up food, or at least not much, it was usually liquid and some hairballs. I was feeding him Iams at the time. I switched him to Science Diet and he stopped vomiting. I think the Science Diet is what actually did...