Hi Welcome Most cases of gastroenteritis are caused by viruses and requires only symptomatic treatment, consuming contaminated foods or drinks is another common cause. You do not need antibiotic and also not anti diarrhoeal agent. But you have taken it (loperamide), kindly wait for few hours. You can take Racecadotril, which is anti diarrhoeal agent. I would suggest you to drink plenty of water or electrolyte solutions to prevent dehydration. Add bland foods to your diet, such as bananas, toast, oatmeal and rice in small amounts every couple of hours. Avoid spicy food. Restrict meat for few days. You can take curd which will be beneficial. Probiotics like Sporolac or Ecobion will be beneficial. In case if your symptoms persist, I would suggest you to go to ER. Hope this helps Take care.