You got many lucky breaks from your opponent.
1) Your opponent won a pawn early in the opening.
2) Your bishop sack lead to nothing
3) Your fork was not at all forced, easily could have been avoided.
4) Even after the fork, you would have still been in a losing position if your opponent played precisely.
5) You really should focus on the lines offered by the chess engine as improvements and try to understand why they are better. Most of us play terribly by the standards of the silicone beasts, but they can help us learn.
I played this game earlier today, and it was a very satisfying win for me (my opponent was rated higher than me), but Rybka and Chess.com engines said I had a losing posistion all the way through. I am posting this game in analysis, because I would really like some advice on my position if it really was bad, or my opponent just didn't respond the right way. Sometimes I just don't understand the engines. Thanks guys, hope you enjoy the game.
A quick edit, I say the fork at H3 in three this was incorrect I think it was 4 or 5. I also put some annotations behind moves I hope this doesn't confuse anyone, sorry in advance if it does. :)
Kerry