Entry from British & World English dictionary
Definition of doodah in English:
noun British informal
Used to refer to something that the speaker cannot name precisely: from the poshest potpourri to the humblest dangly doodah
early 20th century (in the phrase all of a doodah): perhaps from the refrain of the song Camptown Races.
all of a doodah1
Very agitated: they’ll be all of a doodah because of the bombs