I am 14 days late on my period but my test in negative?

Home pregnancy test?: 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.

Blood test for HCG: If you had sex since your last period, get a blood test for HCG level to settle the issue. Visit this site for info: http://www.nichd.nih.gov/health/topics/menstruation/conditioninfo/Pages/causes.aspx