I believe it should be an infection. remember not all vaginal infections are sexually transmitted. Germs could get in through improper cleaning after visiting the toilet and bad or poor sanitation toilets.Germs that usualy cause fowl smells in vaginal infections are usually trichomonas vaginalis
and Gardeneralla. You will need to visit your primary care
physician for a vaginal swab to be done, tests for Gardenerella, yeast, Candidia
, Trichomonas and other bacteria to be done. Culture and sensitivity tests would be very appropriate in this situation. Your primary care physician shall give you proper guidelines on how to clean yourself after visiting the toilet, usually from front to back, and not back to front.
Have a great day as I hope this helps.