It could be another form of bacterial infection. Plenty of different causes for this. Not urinating before & after sex. Wearing thongs. Dehydration. Taking baths/bubble baths. I would get bacterial infections, uti's, ect. And my doctor told me those can all be reasons for getting those infections. I immediately fixed everything I was doing, which was pretty much everything on the list, and I've been infection free for months now! Also, something about the Ph in my husband's semen also caused me to get a yeast infection. My doctor recommended using condoms or you can try the "pull out" method. Just no semen inside you. My doctor actually said a lot of women infections for that reason alone, never knowing that's what caused it.
It sounds like it can be yeast infection... I just got over a yeast infection n it sounds similar to what I was having. But if ur not sure just contact ur doctor to be on the safe side:-)