If this kind of mistake had happened to you then you wouldn't shut up about it and you know it.
I have been fucked by GM mistakes and actions far more times than you have. But, like Elixir's mistake of making Goon immortal, I recovered from it and moved on with my life. I didn't dwell and blame my loss on it. Or DR's decision to clear the spree killer of any guilt which took away the stall lynch target I had planned from the beginning so I could get to the next day and 50-50 coin toss my win, when he wasn't even the host of the game. Or DR confirming on skype that I was soul of the beast before the hammer fell on me. Or one of the many other things that have hindered me from claiming victories.

So I'm sure your first stings a bit, but grin and bear it because it gets easier with time.