Hi. Thanks for your query. Noted the history and understood the concerns. Nidazle whether Ornidazole or Metronidazole can cause GI upset in the form of nausea and vomiting as it causes gastritis. Also can cause bloating, weird sensation in stomach and so on. These are inadvertent reactions meaning usually occurs in many patients and stop after discontinuation of it. Since you have also got a sore throat, unable to sleep and feeling tired I would advise you the following in such a situation: Stop that is hold on the medicine. Consult at ER or your Doctor to have a clinical evaluation so that proper investigations can be done and manged according to the diagnosis. Get stool and blood tests done and an ultrasonography of abdomen to see and rule out for other causes os such symptoms. If found positive, get treated accordingly.