Here the word "days" refers to a lifetime. The idiom "to cut short ... days" means to cause someone to die before they have lived a long life. Alternate translation: "killed them while they were still young" (See: [[rc://en/ta/man/translate/figs-euphemism]])
Asaph speaks of years as if they were containers. Alternate translation: "year after year they were afraid all the time" (See: [[rc://en/ta/man/translate/figs-metaphor]])