Don't worry about it. It could have been some small inane thing, who cares. You know your good at what you do, so they lost out. Try again sometime as someone has suggested.
On the other hand. Many Americans use their jobs to define who they are. If that's the case, see a therapist and get some SSRI's like Paxil. Or go on a bender for the weekend. Just don't go to work drunk on Monday morning.
People are so much more than their jobs!