I used to be like this when i was in undergraduate program. So nervous about speaking that i often skipped classes. I am in post graduate program now and i have literally presentation every day and the thing I have learned is that to hell with the people sitting in front of me and to hell with what they think. I am doing this for me and my career. And most of the people not care if someone stutters. And if they say something behind my back i seriously pity them and their thinking. Just go with the thought that "You are doing this for you and nobody Else". And most of the people will not be with you in next 2 years so let them think what they want to. You will be just fine :)