I had unprotected sex a month ago, but he pulled out. 2 days later i took plan b. 7 weeks later no cycle. my pregnantcy test was negative. am i or no?

Pregnancy unlikely: Home pregnancy tests are very accurate and not affected by foods, herbs, common illnesses, sexually transmitted diseases, or medications. A correctly done urine test gives a reliable result 3 weeks after sex (3 weeks after when conception might have happened) or 1 week after missing a period. By 7 weeks after sex, a pregnancy would definitely show up on a correctly done urine test.