Can someone help me classify my stutter and maybe trace it's origin?

Can someone help me classify my stutter and maybe trace it's origin? I find my stuttering really strange. I don't really know where it came from. I definitely know that it's not the developmental type, since I had no stutter in the childhood. And not the neurogenic too. This only leaves psychogenic type... As far as I can remember it started in mid-school. I was using local buses to get from school to home. Back then passengers had to pay with cash before exiting the bus. Since my stop was in-between the major stops, I always had to say my stop name to the driver before giving the cash. I guess the urgency of the situation made my stutter to the point I couldn't even say the word. But other than this, there where no stuttering back then. I'm 33 now, and it seems it gets worse. Last year I was attending CBT for social anxiety and we had a home task to watch King's Speech movie. It seems for me that after watching it my symptoms got worse. In the situations where my brain perceives that the other person expects a quick reply from me (waiter taking order at restaurant, job interviews, etc.) the stutter onsets. It rarely happens when just speaking with friend casually, when I'm relaxed. But sometimes happens even in this situations if I want to express some idea or joke quickly. Also, I'm affected with this much more when speaking English, since it's not my native language, which adds even more anxiety.