I agree that you really need to talk to the charge nurse or unit manager. Being a new nurse is really tough and having a clinical coach that is making it tougher is a good way to burn out and demotivate new employees, which in the long run increases turnover and lowers morale for everybody. I have been a clinical coach/preceptor for many students and new employees and try really hard to be supportive, to help build on strengths and address weakness as tactfully as possible. It is the coach's job to help the new employee to succeed and that means supporting, not beating them down. Your preceptor is not doing that and the manager needs to know so that she does not continue to drag people down. Hang in there, it gets better, and when you are in the role of clinical coach/preceptor some day, remember how she made you feel and how unhelpful it is.