Have you ever been caught in a tight space, maybe where the air is stale and there’s not a lot of room to move or breathe and you’re sweating because the air is warm and getting warmer and the space is getting tighter and tighter and where the ceiling is moving down and the walls are creeping in and the floor . . . Well, where the floor is pressing up, pushing you toward that lowering ceiling?
May I recommend that you, knowing what this feels like, don’t imprison your readers inside a character’s head.
What this means in terms of the practical is to give readers variety. Rather than locking them for pages inside one character’s thoughts, introduce readers to new settings and action and dialogue and even to the minds and emotions of other characters.