There's been a lot of action with Google recently, I'm seeing some drastic fluctuations in which Google's displaying localized results for keywords that really don't need localized results, ex: SEO related keywords.
Chances are though you weren't affected by this, and it was probably your redesign. My question for you though, did your redesign mean new URLs? If so you've probably lost the "value" of those old links that you had since your new URLs are different. If you did change the URL structure I would either revert back or attempt to 301 each and every old URL and point it to the "new" variation of the URL or the homepage.