Stomach upset with loose motions, gas, bloating, abdominal discomfort, and weakness is commonly caused by indigestion, mild stomach infection, food intolerance, or irritation from outside food, oily meals, or contaminated water. Frequent loose motions can also make the body lose fluids and salts, which may lead to weakness and tiredness. For now, focus on keeping yourself hydrated with water, ORS, coconut water, or other light fluids. Eat simple and easy-to-digest foods like curd rice, banana, khichdi, toast, or plain homemade meals, and avoid spicy, fried, or heavy foods for a few days. Taking small meals instead of large portions may also help reduce bloating and discomfort. Many mild stomach infections improve gradually with rest and hydration, but if you develop a high fever, blood in stool, severe pain, repeated vomiting, or signs of dehydration such as dizziness or very low urine output, you should get medically evaluated.