Hello As per the infomatiom provided May be something at you are eating is not correct or is not suiyubg your body system. Weight gain is a slow an steady process. Healthy muscle gain is what is required at your age A balanced diet will promote muscle  and over all development. In case of non-vegetarians, there are lots of option to select from. For pure vegetarians there are many combinations of foods that promote muscle growth. Lean meats, eggs, Pulses, Soya, cruciferous vegetables, dairy products and whole cereals promote muscle gain. Along side proper exercise and a healthy lifestyle aids in overall developmemt. For tailor made diet plan feel free to contact me or register at http://ghkritediet.zest.md