That is strange. I took a look at your source code, and there isn't even any code for the sidebar. Which means it's not a problem with the layout itself, because I can't make code disappear with css. The only thing I can think of is that you have the page setup set to "no sidebar". If you go to Journal => Customize Journal and scroll down to the bottom, there are three page setup options. The one in the middle - sidebar on the left - should be active.