Sorry, I don't have any advice for you, just wanted to offer a little sympathy. I was dxed with BV at 17 weeks (i'm now almost 23) and they put me on antibiotics to treat it. That left me with oral thrush, but that's a different story. Like you, I didn't have any typical symptoms. I went in b/c I had some real light spotting. They found a polyp and decided to test for BV b/c the two are often related.
I just wanted to say that I know how nerve wracking an infection can be. I've read that BV has been linked to preterm labor. That has me slightly worried even though my midwife as told me the chances are small.
I guess the only advice I can give is to do lots of research and seek a second opinion if you can or feel like you need to. I'm sure my midwife is going to be annoyed with me, but I am going to ask her more questions about the BV when I see her again.
Yeah gardnerella is a pain... I had it with pg #2. I cut out sugar completely, even fruits. I also drank lots of water, ate plain yogurt every day 2x and used a st john's wort/comfrey cream topically. Went back to the midwife the following month and was all cleared up! That does not work for everyone, sometimes anti b's are necessary. True that there is a risk of pretem labor with BV, so consult with your caregiver. Even if you have to take an anti b you can recoup from that with yogurt, low sugar, good water to drink and probiotics if you choose to use them. Do not start them until the couse of anti b's are finished, they are more useful right afterward.