After synchronization I lost my whole Anki decks, they're all gone


for a long time I used Anki without having an account. then I created one because I wanted to synchronize my desktop antis to my phone. after I logged in on my computer and synchronized it, it deleted all my Anki decks. I am now left with nothing.
please help, how can I get my decks back

You can restore your data from an automatic backup.