Disable third-party modules before core update
The one and only way to solve your problem responsibly is the following.


Download all files to your local machine.
Where you have a web development setup. And Drush.
Download the database.
Setup the page on your local machine, import the database and re-do locally what you were currently trying to do on the live server.
Use your local Drush and whatever other tools you can get to check error messages, server logs, debug output etc.
Drop and re-import the local database and repeat every step until you have reproduced the problem often enough to know what went wrong in the first place.
Fix your live page.


And finally:

Never ever again update stuff untested on the live server. And have the database backed up let's say at least once a week. Good luck!