Relax, seriously. Don't get super stressed or super upset. It won't help if you're nervous or stressed out at the interview. Breathe deeply or meditate or have a cup of coffee/tea.... anything to calm you down.
I had advised some people on preparing for interviews. I will post the links a bit later. If it helps to cheer you up: Both those guys got their TRVs immediately after their interviews.
Fret not. Stress not. We're going to prepare you for the interview
Ignore the literal meaning of this. The 'additional documents' refers to the interview