Turned into a real zombie with mine, personality changes and all. Got to the point of not caring if the world continued to turn, or I with it. Tried, but couldn't take it. Finally had ENT assessment, and will have surgery next month to reduce size of turbinates, deviated nasal septum, soft pallet and curtain repair. It won't be as comfortable as the total knee replacement, but the long range prediction is promising.
Good luck with your process.