I suggest posting your question in the gastroenterology forum:
http://www.medhelp.org/forums/Gastroenterology/show/68
I'd also contact a travel clinic or the infectious diseases department at a university hospital.
If Metronidazole (an antibiotic) is the one you took, it's the same as Flagyl. Common adverse reactions associated with systemic metronidazole therapy include nausea, diarrhea, and/or metallic taste in the mouth.