On another blog site of mine, suddenly, all of my posts disappeared, though when I checked the database, they were all there, and repairing it didn’t help. Nor did any of the other fixes I saw online.
Then I checked the error_log (this is a file you find at the same level as the main wp files in File Manager). There were lots of warnings about Psychic PSB.
If you have the same problem, I suggest you check your plugins.