I had been typing a large amount of cards into the Anki app on my Macbook, I then quit the app to go back to watching lecture videos on my computer and a note popped up that I briefly skimmed and It basically said the app and my Ankiweb werent the same so I hit an option and now all of my cards are gone. Please help I really dont feel like retyping them all.
There’s a good chance you can recover your data from a backup:
https://faqs.ankiweb.net/restoring-an-automatic-backup-recovering-from-data-loss.html
To avoid the issue happening in the future, please see: