Green’s Dictionary of Slang

f.f.f. phr.

[abbr. frigged, fucked, and far from home or forlorn, famished, and far from home]

(Aus.) utterly miserable (on account of the war).

[Aus]W.H. Downing Digger Dialects 23: f.f.f. — Completely miserable. (‘Forlorn, famished and far from home’).
[Aus](con. WWI) A.G. Pretty Gloss. of Sl. [...] in the A.I.F. 1921–1924 (rev. t/s) n.p.: F.F.F. Completely miserable; frig[g]ed, fucked, and far from home; forlorn, famished, and far from home.