Why do I go through periods of stuttering?

Why do I go through periods of stuttering? I've been stuttering my whole life, used to go to speech therapy for it. I used to work at a place where I had to say my name all the time and typically did it with no problems. Now, I got a new job and having a hard time saying my name and incredibly anxious when I have to introduce myself. Does anyone have an idea why this happens? I feel like it may have to due with my overall mood and anxiety in general. I am in early 20's and lately just coming to terms with my stutter. Thanks :)