Green’s Dictionary of Slang

1. (orig. US) in difficulties, in trouble.

1899		J. Flynt Tramping with Tramps 393: DITCH, or BE DITCHED to get into trouble, or to fail at what one has undertaken.
a.1909		press cutting in J. Ware Passing Eng. of the Victorian Era 110/1: A portion of Doris’s Inter-oceanic circus was ditched on Friday on the Missouri Pacific Railroad, near Booneville, Mo.
1925		(con. WWI) Fraser & Gibbons Soldier and Sailor Words 78: Ditched: Done for. Specifically a Tank Corps term for a tank bogged or sunk in swampy ground.
1932		F. Jennings Tramping with Tramps 212: Ditched – to get into trouble.
1933		Western Morn. News 19 Sept. 12/4: ‘Two consecutive wet Saturdays and we are completely ditched’.

2. nonplussed, at a loss.

1909

J. Ware Passing Eng. of the Victorian Era 110/1: Ditched [...] Now figuratively used ; e.g., ‘I was ditched completely, and did not know what to say.’.