My period was scheduled to arrive on yesterday, 27th, it never showed. This morning, there was very light brown discharge when I wiped, mixed with a thick eggwhite cm. Now this afternoon, it is fading as I wipe... any ideas? We are trying to conceive, my cycles are regularly 26 days, this brown smear isn't normal for me... thank you for all advice!

Its hard to say. Its very likely that brown discharge (old blood) is the beginning of your period. You may be regular most of the time, but several things can delay our periods (including holiday stress). Implantation bleeding is not very common and IF it occurs it would be around 16 days after ovulation but everyone is different.

If your period doesn't show in a week, take a pregnancy test.