Never update XStore core plugin without theme update. XStore theme is out of date and is not compatible with version of plugin that you updated. Do you have backup of your site before the plugin update?
Restore that, please. After that create staging site (full copy of the production site) and provide us with FTP and Dashboard access to your staging site to allow us to update the theme. Besides, I see that you have a lot of file in your child theme. Did you make changes in all these files or copied a lot of them just in case?
