Hi there,
There are a few other reasons why your vagina will smell terrible; these include infections from Trichomona vaginalis, which gives a terrible fishy smell odor with a yellowish green discharge...th is will make a guy vomit (just kidding), and/or another condition involving bacterial vaginosis; such as Gardnerella vaginalis. These can be diagnose by vaginal smear/discharge through a microscope in a lab. Both are treated differently (metronidazole for Trich and antibiotics for Bac vaginosis. Go see your physician for the proper diagnosis and treatment.
A yeast infection could be the cause too, but, vagisil should of treated it. Since it didn't, it can allude to the other causes.
Good luck.