I'm a singer-songwriter and music graduate who never ever performs, only once in a blue moon with my friends in a band every now and then (as a backup singer). But as I am keen to go into songwriting (for local ads or national or for record labels) I sent off my songs to the local BBC with my singing (I CAN sing, I choose not to follow it through due to my anxiety) and have been asked to perform at a festival this Saturday alongside 3 others to showcase local "upcoming artists". We each have 15 minutes to showcase a few songs and I'm aware the opportunity is the best I've ever had but I performed two nights ago at a local bar to test out my set and though I got through it, I was shaking and hyperventilating. I'm petrified, but as I have done 3 years music performance I do know some calming techniques but I'm really scared I'll start shaking as I did a few nights ago. Any tips?