Irritation in vagina before period?

This just recently started the last couple of months. But a week before my period my vagina just seems irritated. It itches and hurts and has some swelling, even if i don't have sex. (the sex makes it worse) so i try avoiding. It's uncomfortable i don't know what to do! I know it's not a yeast infection or Bacteria infection. And i just got tested so no STDS.