I took planb 5 days after sex since my bf peed before sex which i believe caused the sperm to be flushed out of his precum. can i still get pregnant?

Unlikely: If still worried, can do a pregnancy test. A urine test done correctly gives a reliable result 3 weeks after sex (3 weeks after when conception might have happened) 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. If a woman has her normal regular period, then she is not pregnant, and a test is not needed.