You need to work on your immunity via diet and homoeopathy.
As far as your diet is concerned you need to incorporate immunity boosting food like
1.
Vitamin A rich food e.g sweet potatoes,carrot, mango, pumpkin, melons along milk (& it's products), egg, fish, lean meat.
2. Vitamin C rich food e.g lemon, orange, amla (Indian gooseberry) , guava, kiwi, strawberries, capsicum.
3. Improve protein content of your diet via animal source food, Dal's, sprouts, nuts, oil seeds.
Next Steps
You should cut out junk food from your diet and stick to home cooked meals as much as possible.
Try to get at least 7hours of sleep daily and include at least 20 minutes of exercise 5days a week ... Good quality and quantity sleep along with exercise are known to improve immunity.
Health Tips
For homoeopathic treatment with tailored made diet to suit your requirement you need a detailed case study.