I'd sex 2 w ago,my period(less blood than usual)came at 20 d & lasted 11 d! dr. suggested preg.test, results <1u/l.no possibility for pregnancy,right?

Very low: If a urine pregnancy test is negative once, you're unlikely to be pregnant at this time. A repeat urine test at home if negative can reassure you with high certainty that you are unlikely to be pregnant Best Wishes Dr M

Labs: should recheck home pregnancy test in 2 weeks, just to be sure: time for BC pills and condoms.

Probably: Home pregnancy test are pretty accurate but you might repeat in a week to make sure.