Wordpress SEO

I recently updated my blog on wordpress and all of my traffic has disappeared. I was getting around 60k uniques a month. Now I have 1/4 of that over last couple of weeks. Only difference is the update of blog and all of the plugins to current versions. I have had a few anomolies with jQuery but I believe those have resolved. The reason for upgrade was to protect against TimThumb.php threat. I do not believe the blog was hacked but it is possible.