Hi kitty, I guess you probably have a very late ovulation this cycle so your period hasn't started yet. Did you experience a lot of stress or have any change of lifestyle this cycle? Sometimes even a small thing like travelling can delay our ovulation which will then delay our period to come. I think you can either do another pregnancy test again after 2 to 3 days or go to see a doctor to find out whether you are pregnant or it is just because your period has delayed. Don't worry so much. Tell your doctor and see if he/she can give you a blood test because usually blood test can confirm a pregnancy a bit earlier than urine test.
Meanwhile, take good care of yourself as if you are pregnant. wish you luck!