when to stop dieting and eat portion controlled meals.

My name is sunil,
I go to gym and exercise for about one and a half hour & I am on diet, with no rice, eating only chapati without oil with cabbage and beetroot as accompaniments and whole wheat upma since three months. I dropped 13kg as a whole, 6kg in the first month, 5kg in the second month, and now in two weeks another 2kg. I feel very light. But recently I fell sick due to the climate changes, generally i would recover within a week, but this time it took me 3 weeks, I was very weak, I was on leave for about 5 days. Is this a result of not taking carbohydrate. I drink coffee once in the morning and evening. eat 4 marie low fat biscuits at 11am and have a fruit (orange or water melon(a quarter)) at 5pm. and have 4 to 5 chicken (small) pieces once a fortnight at dinner. Am I over dieting. Please suggest me a diet regime, such that I don't weigh more than what I am now, and decrease my belly fat. I look like one who has all the fat at the belly, the fat I reduced at all the other places in my body has fallen at my belly. looks awkward. Please suggest some exercises to reduce belly fat.

Thanks for reading patiently and suggesting the solution.

regards
sunil