Lost my whole page

I only have a header showing, the rest of the page is missing. It started out with the sidebar, slanting into the text of the posts. It stayed that way for 3 days, then went totally blank. Please give me advise on how to restore it. http://www.nitawatson.com/blog2
nitawatson44@yahoo.com I really need someone to walk me through this, I am so new.