Hello, I Have A Problem. My Vagina Is Really Itchy,

Hello, i have a problem. My vagina is really itchy, and I dont know why. I've had sex a week ago, and we didn't use a condom. But three hours after we had sex, I got my period. The next day, it began to be itchy. The place were my vagina is, something looking like a hymen is hanging out, like around the hole and I just think it's the hymen. But that part is really itchy, and I dont know what to do about it.