Can not log into wp admin due to array warning

When trying to log into my wp admin (I’m running multisite) I have no access and the following error comes up: “Warning: array_flip() expects parameter 1 to be array, boolean given in /home3/adminname/public_html/wp-admin/includes/menu.php on line 193”

I activated and deactivated a few plug-ins in my multisite admin yesterday and both of my sites crashed showing “Fatal error: Call to undefined function wp_get_current_user showed up…”

I thought I had repaired the problem by including pluggable.php into my capabalities.php in wp-includes because my sites were up again. Though when I tried to log in I had the new error showing.

Does anyone know what to do? I guess I might have to re-install wp but maybe there is a better way?