I understand your concern. First let me know that is there any issues with your health or mental stress that induced weight loss? You need to check with the physician about your hormone levels, digestive disorders or any malabsorption issues if any. If all are OK, then it is easier to suggest you a proper diet plan.
Till then you can start having calorie rich nutritious meals like wholesome meals made of cereals like oats, ragi, barley, jowar,atta.
Have lots of fluids throughout the day. Have fruit custard, milk shakes and smoothies,home made with any of your favorite fruits, have banana, chikoo, grapes these fruits. Along with other protein foods like dal, rajma, soya, fish, egg, lean chicken etc. Also can connect to any of us personally for customized diet plan.
You need to check out first tht why there is loss of weight and in how much time as might be underlying any medical issues or digestive disorder leading to less intake of food.daily metabolic rate(bmr) has to be checked to give you right type of daily food intake to increase your desired weight and not fats in your body.high protein foods like beans n legumes helps building muscle mass n foods like seeds n nuts can shape up your body increasing metabolism .daily diet plan will definately help you
plz consult a clinical nutritionist n appropriate testing wil help ur problem
dont just hog on high fatty foodsn sweet products to increase your weight ,u might indulge with other severe problems