Thanks for your query,
Irritable Bowel syndrome
is functional disease of GIT presents with nausea, vomiting, abdominal bloating
, abdominal distention,diarrhea, constipation, flatulence and anxiety.
It is diagnosed by excluding all other condition that may present similar way, like gastroenteritis
specially Giardia lamblia,celiac disease
, H pylori etc
Avoid food and drinks like tea that may predispose symptoms. Take large amounts of wwater.
You are advised to visit your doctor and get stool analysis/culture, upper GI endoscopy, colonoscopy, blood tests, Ultrasound to reach a proper diagnosis.
Hope it helps.