Persistent abdominal pain with nausea and frequent diarrhoea for a week is most commonly due to a gastrointestinal infection, food intolerance, or gut irritation, but since it has lasted several days, it needs proper attention rather than self-treatment. The first step is to prevent dehydration by taking oral rehydration solution (ORS) and plenty of fluids, and eating light, easily digestible foods like rice, curd, and bananas while avoiding spicy, oily, and outside food. Probiotics may help restore gut balance, but avoid taking antibiotics or strong anti-diarrhoeal medicines on your own. Because symptoms have persisted for a week, you should consult a doctor for evaluation (such as stool tests) to rule out infection or other causes and to receive appropriate treatment. Seek urgent care if you develop fever, blood in stool, severe abdominal pain, persistent vomiting, or signs of dehydration like reduced urination or dizziness.