Immediate feelings after the interview

Man, I blew it.
Or at least right now I feel that I did. I should have done the prectice interview and other thiings. There is one particular reference that I should have reviewed. "Typical interview code questions" is a real killer. I am one of those people who cannot type when there is an audience. If someone is looking over my shoulder I cannot code the most simple function in the world. I just go into a brainlock.
If I had practiced on a few of the examples, I may have done better.
On the other hand I always blow the first interview. That's what I am telling myself.
Pretty lame excuse huh?