If I have to read something in front of my class, I'm fine for the first few lines but then I start shaking and can't stop. My voice gets shaky and I feel out of breath. The shaking normally last a few minutes after I finish the reading. I don't think it's because I'm nervous, they're people I see almost everyday and I'm normally calm around them.

It is normal to be nervous when you are the centre of attention and trying to give a speech but it's said that if you're not then you don't respect your audience. If it helps, you could try to picture them all naked - that should help you relax, but try not to laugh too much.