Took plan b 5 weeks ago, and still no period, just a tiny bit of spotting for two days the day my period was due, pregnancy test is negative?

Tests are accurate: Home pregnancy tests are very accurate and not affected by foods, herbs, common illnesses, sexually transmitted diseases, vaginal spotting, or medications. A test 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 negative result may be due to testing too early such as less than 2 weeks after conception.