speaking problem to professional

I am working as a medical representative(sales officer) from last 2 and half years. The problem with me is that now a days i am finding difficult to discuss about the my companys products to the doctors.
MY heart beats fast and i breath fast when i am in doctor chamber. I dont know why this has started happening now a days. In my previous days this problem was not there. I wanna know what is the reason of this, is this becoz of stress or is it any disorder. I have the disorder of speaking and walking while sleeping. I am very angry, anxious and enthusiastic kind of person. I dont have patience at all.
Am i going mad. Is there any treatment for this.

Psychotherapy and Prozac kan help you. But maybe you need another job.