The latest Google update seems to have hit everyone in some way.
From what I’ve seen, you have two options here.
You can try to wait it out and see if it’s a bug (or unintended feature, heh) while doing what you’ve always been doing (adding content, relevant backlinks, etc.). With time, you may spring up again, especially if the changes get rolled back to some degree.
Your other option is to lurk the forums, see what the others are doing and try to work around the issue as they have. There is one downside to this approach, though. If any of the changes get rolled back, then you’ve effectively wasted time and effort.
Whatever you choose, though, I wish you good luck.