Fear is not your enemy. Fear, or nervousness, is usually the initial emotion that signals a problem to be solved. That energy you feel when you are afraid is meant help give you the energy you need to protect yourself.
When fear is out of proportion to the perceived threat, it is a learned response. Not only is your body responding to the external threat, but what you have learned in previous situations is also being remembered, even if it is only on a subconscious level. You will need to figure out the origin of all the stimuli in order to understand how to respond (we sometimes need help with this), but first you may need to simply reduce the level of anxiety.
One good way to do that is through self talk and deep breathing. If you can speak to yourself in a reassuring way, like you would a small child, you can calm yourself. Taking 10 deep breaths, slowly letting the breaths out to a count of 6, will also help calm you. Once you are calmer, you will be able to solve the problem.
Ever wonder where those butterflies in you stomach come from? Here is a video that explains what happens physiologically, and how to use your nervous energy in a positive way.