If your boss is somebody you can talk to.....as a friend.....can you let him know how you're feeling and that you're scared? And that you realize you made an error. Would he be sympathetic? He also needs to realize that as long as he hires human beings to work for him the possibility of an error being made will always be there. I bet he's made a few in his lifetime, too. I do know how you feel, though. I was so ready to leave my job when the time came. It was just too much stress for me to handle and I was always anxious about making mistakes.