Original front page "post" under header is lost

I moved front page (the original “post” under opening header) to become a Page. I wanted that front, home page to be on the menu bar so it could be navigated to from other pages. Consequence: that original front page disappeared from its original location. Now the opening of the website says Page Cannot Be found. –Of course, it is its own page and is on the menu bar. I need to move it back. Please help.

http://www.booksbygretchenbutler.com