Error updating database

I get a blank screen when clicking ‘final manuscript’ on an article. I’ve read articles here that suggested that something is not up to date

Via terminal i’ve run php tools/upgrade.php check and it responds with

Code version:
Database version:
Latest version:
Database version is older than code version
Run “tools/upgrade.php upgrade” to update

I run tools/upgrade.php upgrade and get

DB Error: Duplicate entry ‘6-en_US-givenName-0-0’ for key ‘user_settings_pkey’

I have no previous database backup. How am I able to get this working?