AF two days late, pretty unusual

As of right now, AF is currently two days late. This is something that is unusual to me since my cycles are always pretty regular, about 28 days. AF has already made her appearance on the day she is suppose to, which is always the day Glow suggests/tells me she will arrive. I have taken two hpt, Clear Blue Digital and both have been negative. I took one yesterday afternoon and then today with FMU. Could I possibly be pregnant even though the hpt's are saying negative. I am really praying this is our month. We've been TTC for about eight months, been together 10 years and married four years.