Eat more meat, add some fruits, sleep better, drink some milk before sleeping and alot of water! To gain weight, do it the healthy way, by eating well, just in bigger amounts. Meat+milk= key! Goodluck, stay healthy, and know you're doing good.
Do not worry! I feel like that too but I know all you have to do is work out and excersise. You can also buy Zumba games or even buy Just Dance games. They're really good games! Somewhat expensive though.PS i weigh more than u