1. If you want to get better at giving talks, you have to listen to a recording of yourself. I know it hurts. But you have to do it.
2. Yes, that is how you really sound. It is not playing back at 2x speed.
3. When you speak, you always think you're being way more coherent and intelligible than you really are. Breathe! SLOW DOWN!!
Yours sincerely,
Me