Not able to enter admin after upgrade

Hello all,
After reading posts on this issue, I am still confused on how to approach my problem.

I have been a WP user for 4 years now but am not a developer so please be easy on me…:-)

Since I’ve upgraded my WP version, a few days ago, I am unable to enter my admin.
I get these 2 errors:

Warning: Missing argument 2 for wpdb::prepare(), called in /home/content/i/m/a/imale/html/wp-content/plugins/wp-super-edit/wp-super-edit.core.class.php on line 114 and defined in /home/content/i/m/a/imale/html/wp-includes/wp-db.php on line 990

Warning: Cannot modify header information – headers already sent by (output started at /home/content/i/m/a/imale/html/wp-includes/wp-db.php:990) in /home/content/i/m/a/imale/html/wp-includes/pluggable.php on line 876

I have no access to the dashboard and codes so I don’t know how and where to change things…

Please help!!!
Thanks
Nahama