Well you certainly are your own worse enemy. You need to calm down and stop being so hard on yourself. You have to learn how to be a nurse. It takes time so take your time. You won't make it, if you keep analyzing your every move. You need to know what you can't miss and what is ok to miss and not know and go from there. Many nurses have made the same mistakes and won't admit it for whatever reason, and that is fine. I am lucky to have had some tell me they did the same things I did early on and to they told me to make sure not to do it again. Usually when you make a mistake, you learn from it, but not by beating yourself up. You need to look at what led to the error, and fix that. Were you rushing, if so why. Are you lacking confidence, if so why and now how do you fix these things. Listen to some calming music, meditate, listen to positive talk on you-tube. You don't have time to beat yourself up at work, to much goes on at work, you need to be focused.