My AdSense earnings have also been very low the past couple of days (and today) - I am hoping it's just the holiday making things weird.
To quote Jackie Chan, "Bad Day! Bad Day!" While November has officially reached a point of being my second best month. Today, the day after Thanksgiving in the US, (everyone, except me, is out shopping...) looks like it will be my worst day of the month so far. I guess people can't sit in front of the computers all the time...
I've noticed a similar decrease, about 50%, during the last two days (thursday and friday), most of my traffic comes from the US so I guess this is because of thanksgiving day.