Hi and thanks for the query, The commonest cause of period disruption or lack of periods in a woman of reproductive age is a pregnancy. Other associated syndromes like ectopic pregnancy, ovarian disease and a possible miscarriage must be excluded. Considering the fact that you have a past history of unprotected sex, and this is the first time you are experiencing such symptoms, it is very important that a pregnancy test should therefore be carried out. A clinical evaluation should give much insight into possible causes of these symptoms. An abdominal ultrasound might be of help to appreciate the integrity of the uterus, exclude uterine fibroids that could cause bleeding, exclude cervical disease and the possibility of urogenital infections. Associated symptoms like fever, pain during sexual intercourse and abnormal urination trends might need to considered during the clinical assessment. I suggest you book an appointment with your family physician first for a clinical assessment and management. thanks and hope this helps, Luchuo, MD.