I am Atif, Age 17 yr, height 5'8, I have very low weight about 42 kg. I have allergic asthma since 2 years before I had pneumonia from my childhood, I always been treated by antibiotics tabs, I am very desperate about my underweight I want to gain weight, I eats everything like almonds, milk, fruits, take complete breakfast, dinner, lunch but don't gain weight. What can be the reason, please tell. Thnku.