I did that too. I cried my way through two English classes and an honors class. I have gotten better. However, I still have the little perfectionist in me at work. If I make one mistake, I think I am a bad worker or something. I usually try to remind myself of the good that I do at work. However, my negative thought corrections at work is not as strong as at school. As for solving the problem, I think you have the tools already. It just takes so much hard work that I am not even sure I can ever get rid of my perfectionist tendencies. Keep up the good work.