If you never manually saved that document at least once, then autosave and versioning was not enabled and all content would be lost (and unrecoverable) on normal quit, forced quit, or crash.
If you had saved the document, and there was an unexpected crash or hang, only the content between autosaves that remained in the buffer would be lost. Owing to the frequency of autosave (about ~ 10 - 15 seconds), it is hard to understand how you lost six pages…
You can try accessing past versions (if they even exist) of your document via OliviaMarsh's suggestion, or it might be on your Time Machine drive for recovery.