Unfortunately "practicing" doesn't work if you have a severe stutter, and any anxiety you have about interviews is warranted. The hard truth is that most people dislike observing stuttering and have at minimum an unconscious aversion to it. These people likely include your interviewer and your potential future manager. I would gently push you away from trying to "get over" a fear of interviewing as that fear is simply a natural reaction to the fact that you stutter and your brain is trying to protect you from harm - whether that harm is in the form of mockery, rejection, or shame. In short, you shouldn't expect to get over a rational fear. It's there for a reason. Most people dislike or ridicule stuttering and a job interview is the worst possible scenario for people who have difficulty speaking.