hi there, itching could be due to many other infection besides yeast infection and one of the most common one is trichomonas vaginalis
. That could be the reason why the over the counter drug is not working. You need to vist your gynecologist and get yourself examined and get treatment for the same. Also your parter needs to be treated for the infection as well even though he may not be symptomatic he may be harbouring the infecting organism causing your re- infection. Take this opportunity to get a PAP smear
exam also done if you have not done it in the last 6 months. Take care.