Hi there . Your symptoms may be due to under nourishment. Have sprouts, protein shakes, milk shakes, have vegetables like (potatoes, peas, corn, carrots, winter squash, beets), have fruits like (bananas, pears, apples, pineapple, dried fruit) , if your non vegetarian then have one egg everyday, have chicken and meat atleast twice a week. Have milk and diary products. You can have protein supplements, many protein powders are available in market, mix with milk and have them twice/thrice daily, have more
calcium rich foods.. do weight training exercises, gyming ( it helps your muscle mass to increase and help you gain weight and even increases your appetite and even increase your stamina) hope this helps you. Consult dietician once.