Hai, I will suggest some food to gain weight. As your weight is normal. First eat protein nourished foods like Almond,cashew,channa,soyabean,peanut in your daily food intake. Add jaggery,black gram,and dal prepared with ghee. take diary product like milk,yogurt,chesse,butter etc. Add banana and tuber vegetables. This will nourish in a healthy way and gain weight. Avoid being alone as your in school age try to concentrate on your studies and sports to keep yourself engaged. Avoid frequent masturbation. don t feel guilty. Hope i answered your query thank you