What is actually happening, is your are experiencing just the right amount of stress to heighten all your senses, get blood flowing to your brain and improve your overall performance.
You need a certain amount of stress just to get out of bed in the morning and without it you simply cannot perform adequately.
Stress it’s something that gets to everyone. Here’s a great article on how to deal with it, and even beat it. http://www.mrmoneymustache.com/2012/10/29/first-understand-then-destroy-stress/