What Causes Burning And Itching In Vaginal Area?

alright well. i had pretty dang rough intercourse this last friday.. and around sunday i started to notice that i have terrible burning and itching down there.. i noticed a little cut like thing on my labia. i almost cry when i pee because it hurts so bad and walking is very uncomfortable. i have a noticably large increase in discharge.. i am hoping it was too rough and i am just a little beat up down there. but what could be wrong with me? its only wednesday would an std show itself so quickly?