My pretender died for no reason!

[ceremony]

I haven't had any game end on me yet with my dominion suddenly disappearing. That's not to say such a bug doesn't exist, but with a new player, I would suspect this was simply a dominion loss. Shadowblade, take a quick look at the bullet points in the manual on p. 92. As Honey Badger said, dominion is something new players often overlook, until they feel its ill effects.