What Causes Lower Abdominal Pain Along With White Vaginal Discharge?

My boyfriend and I had sex on the 2nd for the first time the condom broke I suppose to have my period in four days but I notice my lower abdomine looks bigger and I've had white stuff in my underwear and ever time I pee once I get close to finishing my lower abdomine gets tight and when I bend over I have pains? How can I stop everything before my period without a doctor appointment without my parents knowing anything? I'm still in school.