I have read a lot of threads now and I have to say I am shocked how quickly forget their good education when their blog isn´t up and running.
I´d first like to say that I do apprechiate the WordPress application being available for free at all. That does also mean I don´t have to right to COMPLAIN about it. You don´t have that right either.
Mistakes may happen, no one EVER told us to upgrade right on the first day of a new release, this is normally when the more advanced coders go in and try it, debug it and then in a week or so there will be 3.5.1 - DON´T YOU WORRY!
Until then there is a really easy fix to put your mind at ease again:
Go to the version archives and download a fresh copy of WordPress 3.4.2
Then unzip it and put everything except the wp content folder and maybe the wp-config sample file on to your web server. Flush broser cache and log in to your page. It will prompt you to "upgrade your database" you hit OK and it´ll alter it back. As far as I could tell no data was lost from the database. Everything is up and running again just like two days ago.
Now I will go to the pool and drink a cold beer, put my feet in the water and RELAX.
Thank you for your attention!