My daughter is 4 yrs old and has weight 13 kg consistently for past 1. 5 yrs. Also she is frequently ill by day to day cold, fever and vomiting. We have been taking every care regarding hygeine. Also she suffered from chicken pox 20 days back followed by post viral fever. Her cough also is frequent. In past 4 months she has been infected by sometimes bacterial infection, diarrhea, viral fever resulted of lymph nodes at sides of neck, still in small amt visible. Please advice some kind of medicine/immune system strengthening tonic for her