Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. The possible causes of your problem are : -Vaginal infection due to unprotected intercourse leading to lower abdominal pain, urinary tract infection. If symptoms persist, better to consult your gynecologist once, get examined and take local and systemic antibiotics to decrease the symptoms. Taking plenty of oral fluids, 3 to 4 liters of water per day will decrease urinary symptoms to some extent. -If your periods are irregular and if had unprotected intercourse around the time of ovulation, the possibility of pregnancy cannot be excluded. If your periods are regular, as the possibility of ovulation is rare at last week of menstrual cycle, the possibility of pregnancy is also less. Better to avoid sexual life in early teenage as that can lead to many future complications. You should have knowledge regarding ovulation and contraception to avoid these problems in future. Hope I have answered your query. Let me know if I can assist you further.