Has the narrator lost his mind altogether? Or is he, in fact, stuck on a ghost ship? Is he really the rational observer of simple facts as they come to him? Or is he imagining everything thanks to the fact that he's lost at sea? Poe never truly answers these questions in "MS. Found in a Bottle," but the fact that we're asking them in the first place suggests that our dear narrator is viewing the world from a new and stranger perspective. So is his reality in fact reality? Or is it something different entirely? You'll have to go with your gut on that one, Shmoopers.
Everything that takes place after the storm is a figment of the narrator's imagination as he hurdles towards death on a ship lost at sea.
The narrator sees things differently because of his traumatic experience, opening his eyes to previously hidden versions of reality.