Adsense weekend dip again

My adsense earning drops seriously EVERY weekend now...>.<
It becomes not only a one time accident, but a combination of adsense smart pricing, adwords stragery of advertisers and regular dropdown of my weekend traffic.
I dunno what I should do to compensate this drop. Maybe I should work on new topics which attracts holiday traffic~~ Right now my site is stock related and only attracts much traffic when the stock market is open. I hope stock market would never close... hahaha