Hi good to see your query. First thing u need a good vegetables, fruits based balanced diet. For skinny problems is not too big but need natural source foods,no rich junk,processing foods. Avoid constipation. Take max fibres rich foods like whole grains, pulses, salad, greens etc. Plenty of water,fresh foods,early morning rise help u a lot. Sleep min 8 hrs.u can send your mail id vto update more info.

No need for protein powder or supplements to increase weight n immune just take proper nutrition. Mail me  on rekhadadu@gmail.com your complete  diet routine .