Hopper8's 'Odin troubleshooting' guide stickied in General is 'the Bible' for these situations. Find it, try as many of the things in the thread as you need to in order to get a successful Odin flash. These cases are almost always recoverable, and often fixed with perseverance, so it's not a case of trying everything in the thread once & giving up, because that will result in your phone taking an expensive trip to a Samsung service centre/local mobile repair shop or the bin.
That said, I'd be very surprised if you don't get it working again fairly quickly with Hopper's thread.
If it's important enough to cause you grief if it's lost, back it up. No excuses
Trolling for thanks is lame
Does Samsung's auto-brightness implementation crap drive you to self-harm ? A solution !
Failure to search is the leading cause of male impotence on XDA
If you don't know how to recover if things go wrong, what are you doing flashing custom roms ?