Stress is something most of us deal with on a daily basis. Sometimes stress can be a healthy thing as it serves to motivate us to do things to ensure success (i.e. study a little harder, put in a little more practice for the game/recital, or put in more preparation for the big interview). In this type of situation the stress allowed us to perform to the peak of our ability.
For some people, however, stress can be a debilitating thing that prevents us from reaching our goals or even being able to put ourselves in position to succeed. Perhaps you have had an experience where you were asked to speak in front of a group and the night before you were unable to sleep, maybe even developed stomach problems, and possibly even had to call in sick because the mere thought of doing such a thing was too much to bear. Irrational thinking takes over as we sink into survival mode and try to avoid the unpleasant tasks. As a consequence, we may miss out on important opportunities including job interviews and promotions.
It is important to keep in mind is you are not stuck feeling this way. Things can get better.