Hi..I Need To Know What Can Cause Vaginal Discharge. Its

Hi..I need to know what can cause vaginal discharge. Its like white and thick . I saw my on. He did a swab and put it on a slide to look at. He painted me with gentian violet. Said it didn't look to be an std. The PH was high. Should I maybe go back. Take a round of metronidazole? Could this really be an std or just bacteria vaginosis. That was my diagnosis.
I'm a 25 year pharmacy tech. So I'm knowledgeable in the medical field