If you're at the point that you're in therapy over an inability to quit an MMORPG, I very much doubt anyone here can help you.

The only thing I could suggest is putting as many barriers between you and the game as possible: logout, uninstall the game, delete any saved passwords or credit card information, logout of the website, and spend as little time around a computer as possible. You could also try changing your password to something random so that you have to recover it before you can login. Create as many points at which you can stop and reevaluate the decision as possible, so you have as many opportunities to stop yourself as possible. Most importantly, go find something else to do that's even moderately enjoyable, preferably something constructive.