Try soaking in a bath with 2 cups of apple cider vinegar. Vagisil also makes wipes and feminine odor blocking wash, as well as Vagisil powder to use down there (or sprinkle in panties, as it says on back of bottle) for preventing swear and smell. Use Vagisil products, not summers eve. Rub a scented lotion on your thighs and innér thighs after showers. Also soak in baths...apple cider vinegar (organic kind) is a natural and safe, just don't use too much. Google apple cider vinegar for vaginal odor.
It does sound a little bit dietary. Also, sometimes a woman's partner can pass things back to her after she gets over them, so if the last time you used flagyl you continued with the same partner and that person did not take flagyl at the same time, you could have picked it right back up after you finished your antibiotic run. If you're sure this is not it, and if you think it's dietary, try taking old-fashioned "original" Listerine (the stinky kind with eucalyptus) and putting it on a cotton ball and swabbing it on the top insides of your thighs where they join the body. It's great for cleaning up random bacteria on the skin.
Have you used something as simple as vagisil odor block? It also may have something to do with your diet.