Yes I looked at the test within the time frame, it was very faint. I've been using the first response test with the pink dye.
There's a couple scenarios here,
Sometimes a fertilized egg might implant for a short time, your body starts producing hCG and you get a positive test but something happens and the pregnancy doesn't take which makes your hCG fall and your period start. This would be considered a chemical pregnancy.
Another possibility is that the tests could have varying sensitivities within the same brand and maybe your urine was too diluted to produce a positive test (I hope this is the scenario for you). If tomorrow comes and you are still getting negatives but still haven't got your period I would call your doctor and ask them what you should do/what they think.
A blood test might be appropriate here because it can tell your doctor exactly how much hCG is in your system.
Good luck and sorry again that you are dealing with this mind game :(