my 10 year old lab started yesterday throwing up mucus ,he starts when he gets up from laying down with a dry hack then throws up mucus,he eats and drinks regularly but while eating he starts with this hack,the bowl is elevated both water and food,just let him out this morning and he pee'ed so I'm taking him to the vet this morning,should I feed him,we give him a small portion in the morning an a small portion in the evening since birth