@Becky1987,
Good old fashioned stress can make your period late. Annoying, but true.
Plus I believe you took the pregnancy test too early. If I'm not mistaken, the packages generally tell you to wait until you're 2 weeks late. This way, you don't end up with the precise situation that you find yourself in, that you're getting a negative result but you don't trust it.
What else could make your period late? Maybe you've got early flu symptoms. I got the shot in my doctor's office last week so it's possible the virus is already affecting people.
Either way, here's a plan.
Wait until you're 2 weeks past your period due date. If you still haven't gotten it by then, take the test. And then, regardless of outcome, call your doctor, and tell him or her what you told us here.