How to keep a cool head in martial art fighting?

Hi. I do Taekwondo and I'm only a beginner. To be honest, my teacher is not a very good one and it's the only TKD club in my area. So I am seeking some help here on Yahoo! Answers. OK, so whenever I start a sparring fight, I forget all the plans I made before for the opponent after a minute or two. It's so frustrating. I just can't keep a cool head. So what can I practice to develop having a cool head during a fight? I just made up one method. Right after doing some jogging or something to tire myself up, I will just start playing chess or solving sudoku or something like that. So will it really work or will it just make me worse? Any other ideas? Thanks.