The cause of fever is most likely due to acute bacterial infection in intestine. Other possibilities are acute giardiasis due to water borne infestations. In cases of viral infections,fever would have been high or very high and stomach ache will be absent. The problems which you face are not contraindications for paracetamol or cold water. Infact avoid hot and warm foods, because hot diet may form more gas and acidity disturbances. You may take lukewarm diet. First boil Water and than wait for boiled water to turn into lukewarm condition before taking in water. If taking paracetamol per oral is increasing gas formation, than you may take same dose of paracetamol through per rectum route by simple deep push inside anus. Avoid capsule imubless please. Imubless will not help your loose motion problems. Review privately for prescription of medicines.