“Update” function erased post

Hi all,
I was working on a long post (~800 words) that included text, links, graphics and tables. I’m in the habit of frequently clicking on the “update” button in case something unexpected happens. I guess I believed this would save the data in the post in the case of catastrophe.

The WordPress software started behaving very strangely. When I tried to “update,” the changes wouldn’t show up on the “preview” page. After a few instances of this, I clicked on the “update” button and discovered that 90% of my content just disappeared completely. I wasn’t even working on that particular section of the blog, but was trying to resize some tables below the main content. Why would the “update” function suddenly rewrite the database with changes that I did not make (i.e., erase most of the content)?

I’m familiar with backing up my data, however my understanding was the “update” function would preserve any changes made while actively writing/editing a post. The “export” function is like a daily/weekly backup. It seems crazy that I am expected to export my data to an XML file every time I edit a post. I suppose the real question for yours truly is, is it really gone forever? Is there some way of retrieving an older version using an FTP application or cPanel interface? . . .A tired and very disappointed WordPress user. . . AYT