Complete mess (12)
(Other definitions for omnishambles that I've seen before include "policy disaster" , "State of total confusion" , "Riot in Westminster" .)
(Other definitions for snafu that I've seen before include "a mess of things" , "Slangy acronym meaning in total confusion" , "Chaos (US slang)" , "chaos, as usual" , "Customary confusion" .)
(Other definitions for sty that I've seen before include "Animal pen" , "Pigpen; swelling" , "Pigs' pen" , "Sore on eyelid" , "Piggery" .)