Green’s Dictionary of Slang

not plump currant phr.

[a plump currant would be fig. ‘happy’]

out of sorts.

1796		Grose Classical Dict. of the Vulgar Tongue (3rd edn) n.p.: I am not plump currant; I am out of sorts.
1811		Lex. Balatronicum [as cit. 1796].