Code Gone Wild....

So yesterday at work, I was trying to fix this one stubborn bug in our main app. Thought I had it figured out and made a change that seemed small but should have been tested more thoroughly first. As soon as the new update went live, chaos ensued...users were reporting all kinds of issues, nothing worked right anymore. Had to spend hours rolling back changes and fixing everything. Still feel awful about it.... Am I the only one who's had a major screw-up at work like this? How did you recover?