Hi dear ,hope you are fine.
As I can understand that it is so tedious and difficult for gaining weight than reducing weight, but not mpossible. consult Dietician. As I can calculated you need to put on at least 15 kg. You need at least 2500-3000 calories per day for that you need to increase gradually calories day by day. Check up with doctors if you may not have any health issues. And your report should be normal as it is my concern .Don't take
stress . So go for the diet which I tell you like include high calorie foods in your diet whole grain cereal s ,tubers, nuts,whole milk, fruits like banana, shakes,whole pulses,beans,eggs,chicken,fish and also add desserts with every meal. And dietitian will make a
diet plan for you and go for according to it and she can add high calorie and high protein supplement , you can go for ensure plus, it has good results.
Hope I have answered your query.
Best wishes