Can frequent urination be first sign of pregnancy only a week after having unprotected sex? i've beeb urinating almost every hour for the past 16

See a doctor!: Although you may be looking for an early sign of pregnancy (a quick home pregnancy test will answer that question), I am more concerned that frequent urination in this circumstance could represent a sexually transmitted disease (std). Frequent urination is a common symptom of std's, which is why i recommend you see your doctor for testing right away.