So frustrated

So AF is now 6 days late and I'm still getting a bfn. I have an extremely regular cycle, every 28/29 days. I've never been late or early except in 2013 when I was pregnant. I ended up having a miscarriage then. So hubby and I have been ttc for the past 6 months for our rainbow baby. And I'm just so frustrated that I'm getting bfn's when I'm this late! My cervix is still really high soft and closed and I've got thick creamy cm (sorry tmi). I just don't know what else to do or think. Maybe it's time for a blood test! any advice would be appreciated. Thanks ladies!