To be so bored at work that you load StumbleUpon, click on it incessantly all day long viewing random web pages until you run out of suggested StumbleUpon pages to display.

being so drunk that you can't walk or stand properly, but are still with it enough not to just sit down and pass

When you reach the end of Stumbleupon.

1: like cluster fucked, Stumble fucked means to be bombarded by day-to-day bullshit while you have more pressing matters to attend to.

2: to be so caught up in day to day bullshit you are mentally reeling from the impact of even the slightest new thing that crosses your mind

3: like having ADHD on crack.