No matter who you are or what art form you're in you're going to deal with disappointment. Somebody is not going to like you or what you do. Somebody is going to turn a cold shoulder to you or ignore you or worse perhaps,...well there is no worse than being pushed aside for any reason. If you haven't run into that yet you may be doing it wrong. ;) So relax.
Disasters are education, failures are all part of honest training. Unfairness happens. It's a numbers game.
OK enough with the clichés but you get the point don't you? It's never the calamity anyway, it's your reaction to it.
Bottom line, here is a couple things that has helped me deal with setbacks.
Stay positive by staying active, always have projects you're looking forward to, training that is making you better, surround yourself with a circle of friends in the same art form. Believe me, they'll have stories of personal fizzles that will make you feel much better. Shared misery lessens the sting.
There's no such thing as being bulletproof, if you don't hurt at least a little once in awhile maybe you should check your passion for what you're doing.