Gone then.
Not to be preachy (or at least not in a negative way), learn from this. Never trust important document to one place. iCloud sounds like it would be a great backup, but it has a few issues. The main one is that other than the actual backup, the other services are designed for syncing. That means they update almost immediately, and any loss or unintentional errors get duplicated almost immediately.
The iCloud backup itself is good only until it overwrites itself on the next backup. That's daily, if you got it set up for automatic backup (default). That means it's often too late to recover a document before you realize you need to recover. It is also a full restore of the entire iPad, which is almost always more trouble than getting one file back is worth. Though sometimes it is worth it. So, though that method is probably already too late, I suggest you read up on it and become familiar for next time.
So, what I do.
One, I happen to sync with my Mac now and then. The Mac gets backed up every other day or so, and since documents & data get synced to a folder on the Mac, this is my ultimate backup. Time Machine (the backup app) keeps a history of documents so that they can be restored at any point going back.
Second, for really important stuff (of which I have very little) I take the extra minute to save my document to the cloud after each major update. I use Box for this, but DropBox or any other cloud service would work fine.