Im 3 days late for my period. am i pregnant? i had sex for the first time 25 days ago, ( withdrawal method) i took a pregnancy test yesterday and the day before at night, both came out negative. what else could cause my late period?

May retest in 1 week: 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.