It might not be any consolation, but I've had a similar experience. I worked in a call center in my early 20's for about a year and a half. At first when I was making sales, I was able to speak very fluently and with confidence. It seems as the job got harder and as I enjoyed it less, I stuttered a lot more. I definitely had moments on the phone where the contact finished my word for me. And then a manager would call in to my headset and say "Hey, you're stuttering again!" Really makes you feel great at work doesn't it. I didn't stand up for myself even once in those moments. Just gave a stare, didn't say anything. Anyway, onward and upward for you ihtmra, you will get over this experience and find much success. This moment does not define you and doesn't really mean anything. What stands out to me is that you persevered, and as you said you were successful at the job. Kudos!