Some thoughts about the game:
* 2 e5 is a very questionable move. Think about it. You are moving central pieces out early where they can't easily be protected. White ultimately captured the piece because your Knight was blocking you from moving any supporting pawns to protect it. Especially if playing longer timed games, you don't want to push the action as black. Early rushing leads to mistakes.
* 3 Bb4 was also very questionable. You are rushing your major pieces out, a bishop and knight, allowing white to build a pawn structure. All white had to do was move up a pawn and they started building a pawn wall. You gave white a move of piece development while gaining nothing. They got to move a pawn into place at c3 and put you back on the defensive. You compounded the problem with 4a5, backing the bishop up, and letting them create more pawn development on the wings. They could have easily moved to b4 to pressure the bishop and advance more had they chosen to. Backing the bishop onto a5 was a serious mistake and they moved the Knight immediately afterwards to c4 in preparation for a pawn advance to b4 to take the Bishop so you wouldn't go Knight to b4, then Bb4, and take the Knight previously on a3.
* You tried to push them back with 8 g5, but they could've actually used the Knight to g5 and kept the Bishop pinning the Queen, forcing the Rook to sacrifice to take out the Bishop after h4. They were more interested in using the Bishop to triple-team your weakened pawn on e5 though because your dark squared Bishop was stuck helplessly on a5, unable to help out the pinned Queen.
* 9 b7 was a useless, wasted move that allowed your opponent to completely capitalize on taking the vulnerable e pawn which had been completely defended. You could've at least moved to d6 and given it some support. Giving up a key e pawn in a 30 minute game without attempting to defend it was a major mistake.
* In short, your early move sequence set you up for multiple problems and weakened you from the start. You would be better off to just make minimal moves, carefully build up a sustainable defense, and look to capitalize on opponent mistakes. Your choices quickly put you on the defense. Only white's recklesslness on moves 18 and 19 allowed you back into the game, as they stopped protecting their King. They had an opportunity to protect the King on move 19 with f3 or castling but were too aggressive and you were able to concentrate enough attack power in the center to even things up.
* 2 e5 is a very questionable move. Think about it. You are moving central pieces out early where they can't easily be protected. White ultimately captured the piece because your Knight was blocking you from moving any supporting pawns to protect it. Especially if playing longer timed games, you don't want to push the action as black. Early rushing leads to mistakes.
* 3 Bb4 was also very questionable. You are rushing your major pieces out, a bishop and knight, allowing white to build a pawn structure. All white had to do was move up a pawn and they started building a pawn wall. You gave white a move of piece development while gaining nothing. They got to move a pawn into place at c3 and put you back on the defensive. You compounded the problem with 4a5, backing the bishop up, and letting them create more pawn development on the wings. They could have easily moved to b4 to pressure the bishop and advance more had they chosen to. Backing the bishop onto a5 was a serious mistake and they moved the Knight immediately afterwards to c4 in preparation for a pawn advance to b4 to take the Bishop so you wouldn't go Knight to b4, then Bb4, and take the Knight previously on a3.
* You tried to push them back with 8 g5, but they could've actually used the Knight to g5 and kept the Bishop pinning the Queen, forcing the Rook to sacrifice to take out the Bishop after h4. They were more interested in using the Bishop to triple-team your weakened pawn on e5 though because your dark squared Bishop was stuck helplessly on a5, unable to help out the pinned Queen.
* 9 b7 was a useless, wasted move that allowed your opponent to completely capitalize on taking the vulnerable e pawn which had been completely defended. You could've at least moved to d6 and given it some support. Giving up a key e pawn in a 30 minute game without attempting to defend it was a major mistake.
* In short, your early move sequence set you up for multiple problems and weakened you from the start. You would be better off to just make minimal moves, carefully build up a sustainable defense, and look to capitalize on opponent mistakes. Your choices quickly put you on the defense. Only white's recklesslness on moves 18 and 19 allowed you back into the game, as they stopped protecting their King. They had an opportunity to protect the King on move 19 with f3 or castling but were too aggressive and you were able to concentrate enough attack power in the center to even things up.