Unfortunately that is really the only thing I can suggest. You may also try disabling any other plugins besides WooCommerce just in case one of those no longer plays nice with WooCommerce (since they updated some javascript).
If you have the option of an emergency backup with a fee, then that would be your best route if you are unable to replace all of the theme files at once.
Its the big downside of heavily editing the actual theme files and not keeping a log of the changes while at the same time updating a plugin you rely on for income without making a backup/checking compatibility.
Regards,
Devin
