Congratulations on getting back on board again! However...I'd hate to see you wind up disappointed and quit again because of unrealistic expectations and expecting to lose the weight as fast as you gained it isn't realistic. I truly wish it worked that way, but it really doesn't.
As far as your "one golden shot", I don't buy that. It will probably be slower this time than it was before, but it's not impossible to lose the weight again. Stick with it, be patient and keep on going. After all, if this is going to be a WOL from now on, does it really matter how fast you get to goal as long as you get there?
BTW...your birthday is the day after mine. Looks like we were both almost Christmas presents!