Itchy in my vagina

Mariana

So I've been really itchy down there for the past 3 days I recently had my period and I had sex 1 week ago. I need help i don't know what it is it itches so much like you guys dont understand I feel like my "pussy lips" are getting bigger because I scratch it alot and I looked in the mirror and it was really red. Do you guys know what it is? If so what should I do?

Update : I checked my underwear and it's a yellow discharge