Harbinger of AF. Huge temp drop this am. Bad headache yesterday. I expect AF by 4:30. Bfn this AM again on FRER. I'm pretty sure that I o'd on CD 18 now, if AF comes today I'll know. My cycles have been slowly getting back to normal since the September disruption and my luteal has always been 12 to 13 days. I think the extra long sleep on CD 18 raised my temp just enough to confuse FF. If i drop it down even a tenth of a degree it changes O day on FF to Cd 18 ( making me 14 dpo today (soon to be CD 1). I'll update later if she comes (she's usually at the same time of day lol).. I will say, I'll be sad to see the progesterone leave my system, I've enjoyed my pre-af boobies, they look good in sweaters lol.