What Causes A Missed Period With Vaginal Discharge And Abdominal Pain?

HI, i'm 25 years old. i missed my monthly cycle this month. however i had a single episode of mild discharge and no more this month. i had pain in my abdoman region on that day. we usually have unprotected intercourse immediately after my cycle is over for 3-4 day and the following days we have protected intercourse. if i need to see a doctor could you suggest me a good doctor in banashankari area in Bangalore? thanks in advance.