very itchy vagina help!!

So I have a doctors appointment tomorrow but my vagina is EXTREMELY ITCHY. It just started today. I can’t itch it cause it burns and itches even more but I can’t help it it’s so itchy!! AND my period is gonna come either tonight or Tomorrow I can feel it. BUT my question is WHAT CAN I DO? Does anyone know what I can do to make it stop itching and hurting?? Please help this is so uncomfortable. Also has anyone had this before? If so what is it and how long did it last?