Does showering and urinating numerous times clean/kill sperm from last ejaculation? Had unprotected sex 3 days after supposed ovulation accrdng to calendar and pulled out before ejaculating. Pre cum contain sperm? Pregnancy chances?

Yes. Maybe. Little. A urine pregnancy test, done correctly, gives a reliable result 3 weeks after sex (3 weeks after when conception might have occurred), or 1 week after missing a period. If done sooner, a positive result is likely real, but a negative result may be due to testing too soon, and thus lead to a repeat test. If a woman gets her normal regular period, then she is not pregnant, and a test is not needed.