There are two examples I can think of, both music related. The first is "Is anybody going to San Antone" by Charley Pride: Sleepin' under a table in a roadside park, a man could wake up dead.
The other is the title song from a bootleg album by Jimi Hendrix: "Woke Up This Morning and Found Myself Dead".
There are other references that I'm not familiar with but found by searching - a TV show "Woke Up Dead", for example.
I've always assumed it meant hungover or otherwise ailing, but I'm not sure.