Stop trying to write to it, such as with fsck. Shut down the system, boot from another drive, and mount the flaky drive read-only. See if you can get any important files off it. If that doesn’t work it starts getting weirder. Also, is the drive making any weird noises? What is the output of smartctl -a? Do you have important stuff on the drive that is not backed up? Do you have stuff on the drive that is highly confidential and not encrypted?
Best case is that you have backups and your drive is encrypted or uninteresting, so if it is failing then you can warranty it and restore from backups. Are you ok for that if it comes to it?