Hi, Welcome to Health care magic forum.
As you describe, you are definitely
underweight, for your age, and height. If it is genetic low weight, you can get the body with little difficulty.
I advise you to consult a physician for diagnosis and treatment.He may advise you some tests to avoid any chronic diseases, and intolerance to some foods.
He may prescribe you injections of anabolic
steroids periodically, enzymes,
protein supplements, and multivitamins.
Take more calories, fats, green leafy vegetables, pulses ,sprouts, and protein rich foods.
I advise you to sleep for some more time, practice early to bed and late to rise. Try to have day time sleep, for a moment.
Wishing for a quick and complete recovery. Thank you.