I messed up my website!!!

I can’t quite believe that I’ve lost everything. I was trying to add a left hand sidebar following this tutorial: http://www.blogohblog.com/adding-extra-sidebar-to-your-wordpress-theme/#comment-2948632

I added the code and everything disappeared! Even the dashboard, whenever I login, it comes up with a blank page. My website URL clickertraining.siterubix.com is blank.
What should I do?