Hi, Thanks for posting your query. With the available described details, there appears to high possibility of Acute gastroenteritis with possibility of heat stroke. Sunburn is associated with skin lesion not generalized features. You should consult with internal medicine specialist/ gastroenterologist and should go for thorough check up. He should go for complete blood count, erythrocyte sedimentation rate, ultrasound imaging, and serum electrolytes, renal function test. He should take complete antibiotic therapy, antispasmodics, probiotics, antipyretics, if needed. He should maintain your hydration status by taking potassium rich liquids. Take soft diet along with yogurt and banana. Avoid milk and all milk related products. Take care, Dr. Mayank Bhargava