Hello, your symptoms suggest a lower urinary tract infection (cystitis). Sometimes this infection follows sexual intercourse. If you d like to confirm or exclude this diagnosis then a urinalysis may show increased number of white blood cells and bacteria in the urine and a urine culture may reveal the offending organism. I could not suggest any treatment because I don t know if you have a history of allergic reactions to certain antibiotics or you history in general and also whether you ve taken any antibiotic during the last 3-4 months or not. This information is very important for treatment decisions. I hope I ve helped! If you d like more information, please ask and I ll be glad to answer. Kind Regards!