Irritable Bowel Syndrome (IBS) and food allergy

I am suffering from indigestion and gastric problem from childhood days. It is increasing with each passing year. I suffer from severe flatulence and abdominal/stomach discomfort if I eat oily, spicy or sour food. At times there is abdominal pain. The discomfort is less, if the food I eat is not oily or spicy but I suffer from flatulence at all times. I suffer from constipation and there is a feeling of incomplete evacuation after bowel movements. The stools are lumpy most of the times. I usually pass stools twice a day, but the bowel movements increases, if I have a heavy meal or eat oily or spicy food. At times there is severe urgency and the stools are little loose, if I eat food that is more oily.

I cannot control hunger. Within every 3 hours I feel hungry and I have to eat something. If there is a delay, gas accumulates in the stomach with a rumbling or growling sound and I feel feverish. Post having food, feverish symptom is gone but leads to bloating and discomfort. I also get headache(severe pain above eyebrows) due to abdominal discomfort.

I also feel tired and I am not active at work place. I cannot sleep well in the night during following situations.

Too much of work load and work related stress in the office.
Drinking coffee or tea in the evenings (Leads to acidity and discomfort).
If the food is oily or spicy.

I am allergic to oily food. If I eat oily food,there is throat discomfort and I get rashes and small boils or lumps on the skin. Rashes or boils appear after having food or passing stools. It goes off after few hours.

Blood, urine and endoscopy reports are normal.

Due to above problems, my day to day life is getting affected. Please suggest suitable remedy.