You haven't mentioned the date of your last menstruation. A missed period is one of the first signs of pregnancy. There are other causes of a missed period, however, so you don't need to jump to conclusions. Conditions such as stress, being overweight or underweight, birth control pills, and diseases that affect the hormonal system etc. can cause a delayed or missed period. Since the test is negative, and if you strongly suspect you're pregnant you can repeat the test after one week. Meanwhile you should avoid use of tobacco, alcohol or chemicals. Finally, you can proceed to your gynecologist's office to begin the examinations necessary to diagnose any possible organic or functional reason for the missed period.