Can't login

Hello I updated my MacBook Pro to Big Sur 11.3.1 , The update was problem free. The next day I tried to login in to my laptop and my username was no longer recognized. I've had the same login for years so its not that I forgot it. I've seen many post online of people having similar problems after updating to Big Sur. I've tried some of the remedies and they don't seem to work. It's really frustrating because I was in the middle of finals and I lost my notes.