This is normal for Rasmussen. The Liberal Messiah is always between -1 and -25. In a couple of weeks, the poll will be around -5. A couple of weeks after that, it will be around -20.
I prefer using realclearpolitics.com’s averaging of all the latest national polls including Rasmussen’s. The “Presidential Approval Index” from Rasmussen only includes 64% of the total sample.
http://www.realclearpolitics.com/epolls/other/president_obama_job_approval-1044.html