I Had Sex On The 26th And My Vaginal Began

i had sex on the 26th and my vaginal began itchy like crazy on the 28th . but everytime i shower and clean below its okay. Then when i pee it itches again. It has been doing that since the 28th til today. I wiped myself and i see little blood. But im pretty sure its not my period . im not really sexual active and the guy i had sex with was pretty big. Can you explain to me whats going on?