What Causes Bad Vaginal Odor?

hello! I have had bad vaginal odor since about the age of 15 or so. Docotors always just said I will put you on an antibiotic and it will clear right up. While on antibiotics, the smell always disappears. But when I complete the medication, it ALWAYS comes back. I just got some blood work done for my thyroid, the doctor said there wasa low amount of bacteria, nothing to worry about. It seems as if i naturally produce this bacteria naturally. I have been on cipro for a kidney infection and pinkeye/strep throat. The odor always completely disappears, then comes back when I finish the medication. It seems as if it is a bacterial infection becuse the cipro has killed it..I caan never be confident or free..I would love to live on cipro, but I know it is not healthy for m..any advice??