All calendar entries obliterated with 13.2 upgrade

A number of unfortunate and regrettable things happened concurrently with the last (13.2) upgrade, among which was that All Data was removed from the calendar program, which I share with Goodwife. Can anyone help me understand why this might have happened? It may or may not, of course, be related to some of the other unfortunate things which occurred: Time Machine no longer works; itunes won't run because it wants me to sign in with a password, the apple password which used to get me onto this site is no longer recognized (or so it says: I am here, after all??)

Many thanks for any help,

JG