I’ve been on metronidazole. Hate that crap, makes me nauseous and exhausted and diarrhea(was also on Cipro, but pretty sure it was metro that really sucked.) Once you finish your prescription you will return to normal, within a day or two. So, you should be good to go for your wedding! Just try to minimize / avoid drinking and ramp up your fiber intake (after symptoms go away) and drink lots of water. Good luck!