I'm 10 days late and with a very regular cycle, 28 day cycle with a 12 day LP. I use FF and it hasn't let me down. Today I got a BFN :( So I decided to mess around with the settings and found that on advanced settings my O was cd 15 moved to 16 today. But on FAM my O is cd 27 which is crazy because thats when I've ended up with AF the past 2 months. I'm very confused and heartbroken with the BFN's. Any insight would be appreciated .

1st pic ff advanced. 2nd FAM