Student Teacher Week One

I think this last week has been the longest week of my life. Having a student teacher is more exhausting than I thought, and come Monday he will be teaching his first class first period. I'm petrified that its going to go badly, and petrified that its going to be a horrible start to his teaching time. I'm like a mom worrying about her child on their first day of school. Any suggestions on how to give positive feed back and comments would be greatly appreciated!