I don't agree with your assessment of this game.
When you win the queen, Black does have a material advantage. But White's decisive control of the h-file may be sufficient compensation for the material defecit.
Certainly at that point in the game, Black must play very accurately to avoid losing, while White's attack seems to play itself. It's very hard to see how Black can defend himsef, but it's easy to see how White can punish the slightest Black mistake.
Also, Black's play after that point is fairly passive, but it's consistent with Black's earlier play throughout the game. So I don't think you suddenly started playing much differently after gaining the material edge. This is just one of those games where being ahead in material doesn't mean you're automatically going to win.
As any good psychologist or psychiatrist will tell you, the hardest person in the world to analyse, is yourself.
We all know winning "won" games is a nightmare for beginners, and I'm no exception. :(
Please have a look at the following game, and if anyone can offer any advice on how to snap out of "Nursing" mode, it would be greatly appreciated. :)