MIssing Page

I am new to WordPress. With the help of a WP designer I created a blog as part of my website. Everything was great. Yesterday I visited my blog to check on something. To my surprise a menu item failed to take me to a specific page. Thinking perhaps the link needed to be re-established I went to the dashboard, only to discover that the page was entirely missing.

How does a page disappear?

Now my web host is saying that they have to write over the entire blog to try and restore the missing page. This is disappointing. In all my years with a blog, thru Apple iWeb and later Rapidweaver, I’ve never lost blog data.

Is this a rarity or a common aberration?