NL and other languages visible, but English site not visible and showing error after translating news item
From the error msgs shown, it seems that you're using the TB Mega Menu module. So think of a way to get that module disabled (eg using the Dutch admin screens to disable a module, or using Drush if you have it available). That might possibly help to get rid of those errors again.

If you then also unpublish (or delete?) that news item where your problems started from, you may have a stable situation again. And from there continue your investigation to find the real cause (root) of your issue.

Doei!