my cat dennis hasnt eaten for 2 or 3 days and before this he would quite happily eat his food and our other cats.he coughs about once,twice in a day like he has furballs and has been sick once which shot out across the floor,it was just brown liquid.we are keeping him in in the meantime and trying to encourage him to eat,he licks the food as if he's wanting it but doesnt eat it,we've checked to see if anythings stuck in his throat but theres nothing.when he walks about the house he doesnt seem ill?he walks up to the door all the time wanting out,we've tried all the usual tricks,tuna etc but he'll eat nothing,he drinks though,usually water,anybody have any advice?thanks in advance,Lee