AF due but temp keeps rising???

[MelaMommy]

So, I'm definitely no expert, but looking back at my charts for the last 7 cycles, I know that my temp plummets around 9-11DPO, which signifies that AF is coming soon. My cycle days are typically between 24-27 days so that makes AF due today. My temp drop was at 9DPO but there have been three consecutive rises since then. This is very odd. I tested this morning but it was a BFN.

Has anyone ever experienced something like this before??