Sometimes your period can get delayed for different reasons: stress, medication, illness, thyroid problems. If for some reason you didn't ovulate, you could miss your period altogether for a month.
Alternatively, you could have gotten a false negative on the hpt. If you period doesn't show up in another week and a hpt is still negative, you could schedule a blood test at your doctor's office to clear things up. Good luck!
If you keep getting negitive as a result of a pregnacy test, and you are missing your period. You may want to go th=o the doctor so you can get a blood test and if that comes out negitive, then I am sure your doctor will figure things out. I have not had a period for over a year, and I know what you are going through. I thought I was pregnant for a long time and I bought toooo many test..... so to save you from all the worries, go to your doctor...