Sex a week before period which is 4 days late, cramping, lower back pain, thin milky white discharge(moderate amount) took test, it was negative? why?

Trust the test: Home pregnancy tests are very accurate. They are the same tests used in a doctors office. They can detect a pregnancy 7-10 days after conception. The best time to take one is when you miss your period. If you doubt the result you can repeat it in 1-2 days. If you were pregnant the hormone level would rise enough for detection. The discharge requires separate evaluation.