We all work in IT, and we know that things are never 100% perfect. Things happen. We all make mistakes, typos, errors. The best advice is not to live in the past. Don't dwell on previous mistakes. Instead, learn from them, and move on.
But if you have made a mistake, what do you do next? When things go wrong, it's natural to panic, to start thinking about all the bad things that might happen next. That's human nature. As a friend of mine from ITLP says: "Get over it".
When I make a mistake, I like to create a "mistake strategy". Creating a strategy allows me to stop worrying about what just went wrong, and start focusing on making things better.
For example, when I first got into IT, I was a Unix systems administrator for a small company. Really, I was just a junior sysadmin, but I worked alone most of the time because there were only 3 of us on the IT support team, and the other 2 admins focused on the Windows systems.
The sysadmins reading this probably won't be surprised that, as an unsupervised junior administrator, I eventually ran the "rm" command as root in the wrong directory. I wiped out the /etc directory. My first clue was when the command reported that it couldn't delete subdirectories that shouldn't exist in the directory that (I thought) I was in. (Fortunately, I hadn't used the "-r" [recursive] or "-f" [force] options, since I thought I was just deleting some temp/cache files for a program of ours.)
I freaked out! A million thoughts and questions ran through my head: Did I just destroy an important server? What was going to happen to the system? And, would I get fired?
Immediately, I told my supervisor. Despite the urgency, he took a few minutes to do some coaching with me. That helped me to focus. I started to think more about what I was going to do next, and less on the stupid thing I had just done.
We put together a strategy: Don't reboot the server, use an identical server as a template, and re-create the /etc directory. Now that I had a plan of action, the rest was easy. It was just a matter of running the right commands to bring the system back, avoiding a complete restore. And I managed to stop thinking about my mistake.
To be sure, I learned from that mistake. For the rest of my days as a systems administrator, I'd always check what directory I was in before running any destructive command, especially "rm". Learn from your past, but don't dwell on it.
Since then, whenever something goes wrong, I try to put together my "mistake strategy". What things do I need to do, to make things better? And that helps me to let go of the mistake. Sure, I may still think about it, but knowing my next steps allows me to just "Get over it".