User account gone Sonoma

I have the latest Mac Pro M3 14" Sonoma 15.2. I have four users, Admin, Day-2-day, and two I use for website work. I had been using day-2-day and closed the lid for a tea break when I opened and went to go to one of the website users (I had only been there a day or so earlier and last night TM did rather a large and unexpected BU) it went through as if the user had just been created! I tried power down but same. I have a Time Machine backup from last night.

Please someone tell me how to recover all that work for that user.

OhDear! What will happen next!? My Admin account I don't use but is the only one with admin rights. What if that goes belly up!?

Thanks.