Hair loss is often caused by an insufficient intake of the necessary vitamins and minerals. A chronically insufficient intake might be the reason for your inadequate physical growth. You might want to visit your family doctor and have basic laboratory tests done that would check if the level of vitamins and minerals in the blood is low.
If there is no intestinal disorder present that would affect the absorption, then you might want to visit a nutritionist to check if the food you take is inadequate and changes are needed. Taking fresh food, preferably vegetables and fruits, instead of food rich in fat and carbon-hydrated beverages is recommended.
Taking small amounts of meat (preferably chicken or fish instead of beef and pork) to supply the amino acids and other molecules that are not produced in plants is necessary.