Don't Let it Get You Down
Failing is tough. No matter how many times you fail, each one will have the same soul-crashing effect. The important thing is what you do afterwards. You need to learn to not let it get you down.
Fail, learn from your mistakes and move on. Do more work, try again, fail, until you have reached success. Don't listen to the bad things people might have to say and don't change the core of what you are trying to do. You know why you are doing it, it's just not ready yet.
I was amazed to read last week that Tim Westergren from Pandora was rejected 300 times by VCs when looking for funding after the dot-com crash. That's not a typo, it was 300 times! I'm sure the last rejection hurt as much as the first one. The important thing is that he didn't give up. He knew he had something, he just needed to continue trying.
Don't give up and don't let a failure get you down. Gather up the pieces and keep trying.