Super itchy down there??

I’ve been on my period for about a week now and ever since it started, maybe a day or two before that even, I have been SO itchy down there. Everything on the outside itches and a little on the inside as well. There’s no way it could be an STD, I’m not having sex, and there’s very little if no possibility it’s related to a yeast infection because I’m on my period. I think I’ve had something similar to this before but i remember it clearing up and not being an issue after maybe 3 days. Help??