possibly when black played bg4 you could of played h3 becasue he was forking your knight and this woul dof either forced the bishop away or you swap a knight for a bishop.
Also on 17. nxd4 you were lucky to get away with it...
other than that a fairly good game against a good player
You don't need us to tell you that you let your queen be trapped. Just spend a minute pondering what your opponent is doing before you move and you'll avoid disasters like that.
Fwiw, I'm not a fan of your opening line. I know it's orthodox among a lot of people that beginners play the Italian game, but I never had success with it when I was learning. The straightforward 1 e4 e5 2 Nf3 Nc6 3 d4 will give you immediate activity, or if you want to play 3 Bc4, learn the Evans gambit, e.g. 3...Bc5 4 b4 Bxb4 5 c3 Ba5 6 d4
Here's a list of some mistakes that took place in the game.
5. bg5, this manuever will always be fended off easily with a pawn which leads to your opponent chasing your bishop around the board while gaining position. Only the most naive of opponents would not defend their queen in some manner.
8 qd2, i'm not sure why you wanted to castle on queens side considering the slanting of the pawns and the power pieces black has in play on that side of the board. Basically you are moving the queen out of the road for a castle while not establishing any new ground with moving her. While castling is normally a great defensive play, one should be aware of the board position and manner of the game.
10 ne2, I can understand the wanting to free a piece but where's the next location for the knight? The black pawn covers d4 and f4, meaning you plan to move it to g3 which is retreating from the side of the board with all the action. This manuever also opens the door for 10... d5 which breaks down your defenses. Had your knight stayed in place, you would have been able to defend the assualt. Also, this move pins your queen in.
13. qxd4, You have 2 knights that could have taken the pawn instead. That would allow you the room to manuever your queen away from the e5 pawn after it takes the knight, meaning you lose only 2 points instead of 8. Always assess the situation and options fully. Even if you were forced to lose the queen, it would have been better to have moved it back to d2, where you could recapture the bishop. While the lose would still be devistating, you could loss less.
15. f3 there's nothing wrong with the move, but the comment "please" is worth commenting on. Similiar to the 5 bg5, one shouldn't base their attack soley on the hopes of one's opponent ignoring a direct and open attack.
17 nxd4, you are throwing a knight away for a pawn (the rook on d8 can caputre without fear of retaliation.
17.... qa6, Ignoring the free knight, black is setting up for mate. Hoping you take the bait and 18. a3xb4 with 18... qa1 mate. Even if you don't take the bishop your king is in danger.
18. nxe6, black seems to be overly confidant at this point. Already up several points, they ignore much of the field and go straight for mate with little regard for the rest of the board.
19. nxg7, this move makes no sense at all to be blunt. Your king is under attack and not only do you not come to his aid, you opt to take a free pawn instead of the rook at d8 (not that you are in a position to trade pieces, still you would be up 2 points in the deal instead of 1).
19... nc6, black decides to sure up the attack, but now white can capture the bishop with the pawn and the king can escape through d2. Blacks recklessness opened the door for a possible miracle comeback after an early queen loss.
22. bf7, This move is without reason. Your king is being attacked, and you remove a defender for nothing.
28. nh5, though the ending my be a formality, wasting pieces to capture a pawn duing this stage of the game is without merit. Arguable you could attempt to use the 2 rooks to give the king breathing room from the queen.
30. bd5, clearly you forgot your pawn was pinned to your king; though this may be due with the enevitability of the endgame.
I hope that this helps you to improve your game.
I finished this game a while ago, but I haven't gotten to posting it until now. What did I do wrong?