That's odd to not get a positive if you have either bacteria or yeast overgrowth. BV is treated with antibiotics so that you can't treat yourself nor would I. The other thought is that maybe it is fungal without being yeast per se. Estrogen levels go up and that is often linked to yeast and fungal overgrowth. I would try to change undies often, wear only cotton, let yourself air dry at night, eat or take a probiotic supplement or enhanced food (like yogurt or the drinks), and cut down on sugar. Your doctor is not wanting to treat you for a yeast infection? That itching must be a pain! Try some vagisil wipes on the outside to see if that gives you any relief. good luck and soy about this! When are you due?