Although stage fright can be devastating, it is not a permanent or life-threatening ailment. Be encouraged. You can begin to exchange fear for confidence even under enormously high-stress situations.
So, what's the antidote for those "deer-in-the-headlights" moments? Is it more practicing, deeper breathing, more singing, more listening, more mouthpiece-buzzing, more thinking, or being super-resolute? All of those are important, but very likely your secret weapon has not been adequately utilized.
Simply put, your enthusiasm for what you are about to perform must be greater than your nervous doubts. By instilling this mindset firmly on a daily basis, you will be building an effective strategy that will withstand the paralyzing trauma of stage fright.
Bottom line. Strengthen your passion for music. Approach each etude, each excerpt, and each solo with a zeal for its musical message. Resist boredom. Inspired beautiful playing always matters. This applies even to your warm up. Aiming for musicality and expression is what fuels your success on stage and enables you to overcome nervousness.
Your job is way more than just producing notes. It brings into play the very reason we are invested in music. Without a strong consistent dedication to music-making, we become easy targets for the assaults of the dreaded nerve giant.