Go visit your doctor so she can rule out if its yeast or a bacterial infection. I wouldn't mess around w that over the counter stuff! Your doctor can prescribe you something 10x better if there is an issue!
It's probably a yeast infection maybe? Ive gotten lots of them, and sometimes i do get itchy down there right before my period, and then after wards I'm ok. If it continues to itch, you should probably get some vagisil cream or hydrocortisone cream. Oh and try to resist scratching it, because it's extremely painful if you do.