This isn't exactly a time loop story, but the theme seems kind of similar, and it was published in 1967: https://en.wikipedia.org/wiki/I_Have_No_Mouth,_and_I_M

This isn't exactly a time loop story, but the theme seems kind of similar, and it was published in 1967: https://en.wikipedia.org/wiki/I_Have_No_Mouth,_and_I_Must_Scream https://en.wikipedia.org/wiki/I_Have_No_Mouth,_and_I_Must_Sc... There's also "time loop" stories like https://en.wikipedia.org/wiki/All_You_Zombies https://en.wikipedia.org/wiki/All_You_Zombies (from 1959), which aren't really the same, but then as I think about it, how exactly are they different?