Yeah, don't worry about it too much. I've seen this scenario on many occasions. When you do a complete redesign of your website, you usually drop in the rankings dramatically. You should climb back up in a little bit.
It takes awhile to climb out of the sandbox. However you should continue to build quality links in the mean time.
It varies greately, but in my experience if there is nothing wrong with the site, you can climb out within a week or two. Keep in mind that it also may be a MONTH or two as well...
Well, sandbox is theory so we don't really know if it even exists. In my opinion it does, and applies to websites either randomly or to those that my appear like they will switch content into something completely different after being indexed and ranked. I might be wrong though...