I am 17 days delayed. i tested negative in pregnancy tests for every week i am delayed. i had no sex since before my last period. today marks my 52th day of my cycle. could i be pregnant?

Tests are accurate: 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. If done sooner, a positive result is likely real, but a negative result may be due to testing too soon.