TMI but...

Laura

So, I've been having problems with itching down there (Mostly near the vulva). I've been tested for ever STI except herpes and have come back clean. This happens every so many weeks, usually right around the end of my period. I don't have any breakouts that indicate an STI and no other symptoms. Anyone have any thoughts? Should I get tested again or does it sound like a yeast infection or UTI? I'm totally at a loss. Thank you!