I actually have the same problem except I am going to the doctor today, I am actually 11 days late and about 10 hpt's negative :(
I hope to pregnant, but I am one who always tests negative until 8 weeks...just keep waiting, it is hard, I know.
may it just late period nothing to do with pregnancy some times this happen when your menstrual cycle is regular. its just irregular periods nothing to worry, but if u want go see a doctor to confirm it.