UI can't be accessed
As per your "after I re-enabled the modules": try to (temporary) increase your PHP memory limit (eg with 25%) to see if you get different results ... Doing so might get to work it as normal again.

That's one of the typial things I (temporary) do if such kind of issues come up (typically after enable of 1 or more extra modules due to which the current memory limit is not sufficient anymore).