Hi, my cat which is a Male 10 years old and always an in-door cat, has been acting strange lately. Its been on dry food all its life without any problems. In the last two months, it cant seem to keep its food down. It thrown up pretty much all of it at a time. I thought that it may be eating to much, so I downsized its rations, but that doesn't help. If the protion is small, sometimes it just throws up a lot of foamy type spit. HELP?