Herpes? Std? Or just irritation?

i had sex about three days ago, right after i noticed itching almost like irritiatkon its been going on still since today. no burning etc just itching ,reddness and pain when i wipe. its only in the one spot on the lower part of mu vagina right below the opening, it wasnt like this yesterday. what could it be?

kinda looks like what i have and im positive for chlymadia and yeast.