Ok for the past maybe year i get a yeast infection every time before my period. why do i keep getting reoccurring yeast infections?

Recurrent yeast: Make sure the diagnosis is correct. Other things can mimic yeast. If it's yeast, such frequent symptoms are not due to new infection each time, but flare-up of a continuing infection. Talk to your doc to confirm the diagnosis. If confirmed, ask about a prescription for fluconazole (Diflucan) pills. Taking it once a week usually is highly effective in preventing recurring yeast symptoms.