Kitten not eating

[Arri]

Okay so, my barn boys have been doing great until now. On Monday Kooper started vomiting (3-4 times, thick yellow bile) and then I noticed he was not eating. My husband had switched their food and Buddy was fine so, I thought Kooper may not like the new food so I gave him the canned food but he just sniffed it and walked away. I have been trying everything to get him to eat with no success. I have been calling the vet. who said "it's normal for them to vomit occaisionally" (not very helpful) if it continues bring them in.
This morning Buddy apparently vomited as well, this has gone on far too long and I am completely freaked out and worried sick. I want to take them to the vet. but hubby says it's just a flu or something minor. HELP!!!!!!!