What Causes Lower Abdominal And Leg Cramping With Brown Vaginal Discharge?

Hello doctor I had my menses due 4 days ago.. i doubted pregnancy due to unprotected sex last month.. however i carried out a test using a pregnancy detection kit but used an evening sample for that. So that leaves me unsure of the negative result. I would like to add that from 4days i have cramps in lower abdomen n legs and my sanitary pad gets stained with a little amount of white n brown discharge having a strong smell that is had during periods.. but having no bleeding at all. Please guide what to do next