I can't answer when someone asks what my name is.

I can't answer when someone asks what my name is. Hi, I have had a stutter ever since I was able to talk. I'm 16 now and it barely even exists anymore because I invested so much time into therapy for it and I have perfected it. I've had this problem for a while and I dont know what it is or what to do. So today I went to sign up for a martial arts class and when the guys asked for my name I couldn't physcially answer it. I got really anxious and just started coping and going "ummm" and "yeah." It was really bad this time and they were looking at me weirdly. I can usually talk but when it comes to that one question my stutter just kicks in. Like obviously I know my name but for some reason it always plays up when that question is asked. I'm really really embarrassed, and I have no idea what to do. Im here to find out if anyone else has had this happen to them and how I can fix it. I have a little bit of social anxiety and I was also very tired but I dont know if they play a factor in this. Thanks.