I had BV during my first trimester and took the medication with no complications. I recommend taking the pills with milk instead of water; when I took them with water the pills dissolved on my tongue (and boy do they taste awful lol).
As for washing, just use water and a wash cloth. Soap dries out the vagina and leaves residue which causes irritations and infections. Also, check what the ingredients in your lubricant are. Make sure it's a water-based lubricant with no alcohol, sugar or yeast in it (glycerin and silicone-based are also ok). Alot of women don't realize what's in their intimate products and it can cause a lot of issues for pregnant women.
If you're experiencing discomfort/irritation after the antibiotics, there are "yogurt pills" you can take. Basically it has the same active cultures as yogurt but won't upset your stomach the way milk products can during pregnancy. They worked wonders for M. and I was right as rain after only 2 days. Ask your OB about the options.