strictly out (of) luck.
Vulgar. shit out (of) luck.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Word Origin and History for s.o.l.
initialism from shit out of luck (though sometimes euphemised), 1917, World War I military slang. "Applicable to everything from death to being late for mess" [R. Lord, "Captain Boyd's Battery A.E.F."]
Online Etymology Dictionary, © 2010 Douglas Harper