Been tested for all infections and stds. everything negative besides had bv. was prescribed flagyl, and the medicine made me feel much worse.whatwrong?

Hard to say: Flagyl can produce a real uncomfortable reaction in anyone consuming even the token amount of alcohol in a cough medicine. You could also have an individual intolerance to the drug. I doubt it has anything to do with the BV and there are other ways to treat that. I would follow up with your doc & let them know this has happened.