Try the browser's Back button. If you get to where you were before the change, it is likely that you are still logged in. Click the Help link to be sure - it opens in a new window and can be closed later.
Saves having to key in your login details.
This does not apply to timeouts
I'd also like to know how to get rid of a blank adgroup.
Pretty straightforward, really. Just delete the 'blank' Ad Groups, then select either of the following options near the top left of the page at the campaign level of your account:
* Show only active Ad Groups
* Show all but deleted Ad Groups
This is a 'sticky setting', and will prevent you from seeing deleted Ad Groups until you change it to 'Show all Ad Groups'.
AWA