Been there, done that. Had a 7 day cruise turn into a 9 day on Navigator of the Seas back in Hurricane Frances. There's nothing more frustrating than not knowing when you might be coming home.
Past Cruises -
Carnival - 20 cruises, 106 days (Platinum)
Royal Caribbean - 2 cruises, 10 days (Gold)
Norwegian - 2 cruises, 10 days (Bronze)
Disney - 2 cruises, 8 days (Silver)