Sydney Update Causing Critical Error in Website

Hello, I have been using the child Sydney theme on my website: https://www.erikastravelventures.com/

I recently updated the theme on Feb 13th, and it caused my website to completely crash. First, the error stated “there has been a critical error on your website”, and now all it says is:
www.erikastravelventures.com is currently unable to handle this request.
HTTP ERROR 500

I am unable to access my blog or my wp-admin site, so I can’t activate/deactivate plugins or even revert the Sydney theme to a previous version. Can someone from aThemes help me please??

Hello, please check this topic:
https://wordpress.org/support/topic/sydney-fatal-error-after-update/

Please feel free to ask any other questions that you might have.

Kind Regards, Roman.
aThemes Support