Don't worry so much. It's ok, really. I've lost several snakes, and while it hurt me, I didn't lose much sleep over it.
Just be thankful corn snakes are easily, and inexpensively replaceable. Go out and get you a new one and focus your attention on that one. Just make sure you learned your lesson the first time, and keep the lid on tightly and you'll be good to go.
Have faith, yours might turn up sometime when you least expect it. You've done all you can do, now it's up to your snake. =)