At least you were told.
Getting fired is common in this business. If you are not fired at some point, you are not doing something right. I am sure all those things you listed are true and there is nothing wrong with feeling all of them. What you should do is decide if working that level is what you want. Not everyone is cut out for that level (on court and off court). If you decide that working that level is fun, then continue to attend camps and try to get hired by someone else. And if you were fired based on your performance and you feel it was wrong, go back to the camp.
If I were you I would look at this as an opportunity rather than just a failure. This situation just might make you a better official in the long run.
Peace