Yuck! I'm so sorry you are on flagyl! I have taken a it a few different times with horrible side effects. It even gave me what they call "persistant diarreah." Imagine that--a drug giving a person with CD persistent D! I also had horrible nausea, headaches, etc. But it did seem to put me in remission (in combo with Levequin) for a few months.
I tried to eat a little something every few hours to curb the nausea. But because that was the only I could tolerate, the taste of saltines and chicken noodle soup would make me sick!