This is my opinion. I'm not a doctor, so this post is solely based on my experiences.
I always get UTIs while pregnant. I only took antibiotics for it once when I couldn't kick it myself. Otherwise, I drink tons of water and cranberry juice alllllllllll day long. I do 1 part cranberry to 3 parts water, and I often see people ask what a "part" is, so I will explain real quick. I fill a cup 3/4 of the way with water and then finish it off with 100% organic cranberry juice. Make sure it is real cranberry and not cranberry cocktail, and preferably organic, but I know that not everyone can find or afford it. Non-organic will work, too. The only ingredients should be cranberries and water. Limit intake of any other sugars - fruit, snack cakes, ice cream, etc, until you're feeling better.
I would also be a lot less concerned about treating BV naturally. When antibiotics are used for it, it tends to come back anyway. For many, it's a battle they just can't win, even testing clear but still having symptoms. For this, probiotics. I take Garden of Life brand, which I buy from Vitamin Shoppe here in the US. You could probably find a different brand where you live, but the point is that they don't say "do not take while pregnant" on the bottle. Other kinds are safe, but they'll all tell you to ask your doctor or pharmacist, so go ahead and run it by them. Probiotics also help to heal UTIs, so you're taking care of both issues with this. Also, add raw garlic to your day. I go for 3 cloves per day. I personally chop it up and put it over a piece of crusty bread with some olive oil and herbs, yum! Some people will just chew it up, but I cannot stomach it, and it burns my mouth.
Check out this article:
https://www.ncbi.nlm.nih.gov/pubmed/17633390