The next time you make a mistake and catch yourself in yet another never-ending cycle of self-derision...
You're probably overreacting.
Then imagine someone else, maybe someone you know or a total stranger even, making that same mistake. How does it look now? Chances are that sure, you think they made a mistake, but you don't think it is that big of a deal.
Now imagine if that person keeps beating themselves up over it for hours after the event, so much so that it tears a big gaping hole into their self-esteem, the negative effect of which will start leaking over into other aspects of their lives in the long run.
Unbelieveable? Unnecessary? But that's how you too were behaving a minute ago.
We all need objectivity in our lives. It is hard to look at ourselves and judge our own situation realistically. If you don't have someone with whom you can discuss things and get an objective opinion, then just take yourself out of the situation and imagine you're watching someone else go through the same issues. I'm not saying that this approach will make everything seem unimportant, but I can guarantee you that it will end the nightmare of your taking every single thing unnecessarily to heart.
Most of us are way harder on ourselves than we need to be. You wouldn't dare yell at other people if they broke a plate or ruined dinner by mistake, then why would you be so cruel to yourself about similar things?
Think about that.