I often use mantras to clear a "head space" for myself. Here is one I came across that is said to help soothe the nerves, and aid relaxation. It is the bija mantra, or seed sound SOM ( pronounced "sohm") Repeat it to yourself until the body and mind, feels calm and relaxed.

Om is the original and most powerful mantra. It is the primal sound of the divine in its essential manifestation. In the beginning was the word and the word was God (Om).