I also got the femara headaches...usually the last two-three days or so on the pills.
I did one cycle on Femara and had migraines and a fever beginning on the second day of taking it and ending the day after I stopped-- yet my Dr. is reluctant to think there is a correlation! It was seriously horrible. The positive side is that I got my best follicle and best lining while using it... but no BFP. You could call the Dr. and ask about stopping the meds early if it doesn't clear-up today. I can't imagine 4 days vs 5 would make that much of a difference.
I don't typically get headaches, but during the 4 cycles that I took Femara, I got them each time, particularly after O. At that time, I remember reading somewhere that headaches are the only symptom that are typically worse with Femara vs. Clomid. Hopefully it works for you both soon and you don't have to endure the migranes anymore! Best of luck. :)
YES! I started Femara on Tuesday and by this morning (Thursday), I have the most horrible migraine I've ever had- and I get migraines occassionally. So far, none of my migraine or tylenol or natural medicines have touched this thing. Caffeine helps a little bit, but so far I haven't found the cure. Guess I just have to wait until this round is over.