My 5yr old son is losing alot of weight, his eating habits have changed, he eats less than before, he also has been eating more candy than usual, he had pneumonia 2 and half months ago for the 2nd time this year and since then he has just been losing weight, I don't know what to do, he also says he doesn't feel good, everyday I ask him how he is and he says the same thing everyday. Im so worried about him, what do you think is wrong with him?