Let's face the facts here, sometimes life is about attempting not to fail. Occasionally, we can't let go of "learning moments" wherein we did a less-than optimal job.
Personally, I think this is a mark of someone who is constantly holding themselves to a higher standard. This is a fantastic trait but people like me can take that desire for perfection a little too far. That in itself tends to drag me down. Sometimes I'm my own worst enemy.
"Everything in moderation, including moderation." -Julia Childs
Keep doing the best you can and keep improving along the way. Recognize and accept your losses as learning moments and set yourself free of the guilt associated with it.
Process your situation and move forward. It's the only way to maintain your sanity and continually be the best you can. You're only human you know.