38pounds like even less than 18 kilos... that is something alarming for a 11month old Labrador. Get your vet to examine him. There is no harm in changing your vet or taking a second opinion. If he cant help, i'll personally suggest Dr. Rana in Neeti Bagh, New Delhi. He would be of help only if you are in delhi. He is a real good vet, i can say this from personal experience.