Hi Gina and welcome to the bb

! A couple of possibilities came to mind when I read your post. First, you might be pg, but just testing too early. You might have ovulated later than usual and so even though you are "late" when comparing to past cycles, not enough HcG has built up to be detectable on an HPT. Or you could be pg, but be one of those people who don't get a ++HPT for whatever reason. Up to 10% of pg women will get a false negative when testing at the time AF is due and some women never get a +HPT at all (but a blood test shows they are positive). Or you might not be pg, but ovulated later than usual and so AF will come later than usual. Finally, the last possibility is that you didn't ovulate at all this month. In that case, you might start bleeding on your own or you might have to jump-start your cycle again.
Even if you are usually very regular, it's possible to have a "fluke cycle" now and then when you either ovulate later than usual or don't ovulate at all. As long as your cycles resume normally the next month, these flukes are nothing to worry about.
If I were you, I would test again tomorrow as you plan to do and if that test is still negative, I would go see the doctor and get your blood tested for HcG and also progesterone to see whether you ovulated and whether you are pg.
I hope you did and you are

! Good luck and keep us posted++++++++++++
Maura
p.s. What kind of testing have you had done? Do you have a diagnosis? Have you been to an RE or just an OB?