dont worry
U can always restart by( vol up+home+off button) into CWM
flash some kernel like abyss and after restart go into CWM again
and then U can restore your backup nomally
or
you can go into download mode and flash by windows odin by PDA
ROM like LA6 or some else
I had a similar problem tonight i used this thread, which confirms what is said above.
http://xdaforums.com/show....php?t=1507329