What Causes Yellow Vaginal Discharge, Abdominal Pains And Cut In Vaginal Wall?

im a 16 year old girl. i live in tanzania but currently schooling in SA. so that explains why i havent been to any doctors. a week after i arrived, i started having yellow vaginal discharge. i didnt take it seriously till i had abdomenal pains. later on i noticed a small cut on my vaginal wall that was giving the discharge a bloody tinge. the flow was heavy and still is. now there are small "pimples" on the vulva. there are small painfull cuts around the vagina (on the vulva, between the anus and vagina and beside the anus). plus the discharge is still thea. i havent had my periods yet this month as they are due sometime next week.