Where did I go wrong ( 1200elo)

So in this game, I somehow did not do so bad, but somehow around around #25 I kind of just threw the game ;

First, I'm not too sure where I went wrong, it feels like a series of mistake and I kind of want to understand what I did to lose
I mean, move-wise yes, but did I lack strategy, or should I have kept pressuring more, or protect my pieces better, I'm kind of a noob so any advice on how I can get better is welcome ! Did I tunnel vision on something ?

I chose to come here because I really felt good about this game until around #25 I just switched my grin for a :thinking: face lol...

What should I work on ?

You went wrong on 28 cxd5??, when you should've taken with the queen instead of the pawn, which allowed your opponent to penetrate your position and win material back(you made some other mistakes later but 28 cxd5 was probably the main cause of your loss.

EDIT: You also made a mistake when you played 29 Qd1

At the level of skill you are at, you could benefit a lot from learning to see the entire board, (i.e no tunnel vision), and from deeper understanding of tactics.
The training puzzles provided by lichess will help you do both of those things.
To get to them, hit the LEARN button at the top of the page, and from the drop down menu select puzzles. The computer will give you a position and ask you to find the best move.
I think that this is probably the best thing that you can do right now. Once you get more efficient in the two aspects I mentioned above, games like this will almost never happen.

Better players than me, feel free to correct me if I am wrong.
@Senpai-Noticed , if you have more questions, feel free to ask!
Hope that this helps.

@ChessMathNerd is right @Senpai-Noticed. Also, your main blunder was a pin. You can practice pin positions in "Practice", which is in the drop-down menu @ChessMathNerd mentioned.

@SlicingBishop2006 , look at our rapid ratings!!!!!!!!!!!!!!!!!!!!!!!!!!!!

lol same.

Thanks a lot, will do those puzzles !
@ChessMathNerd
You say the 2 aspects, which are tactics and seeing the entire board,
I know generally what it means, to see the entire board, but I still would like to ask if you can go more in-depth about that ?

How do you 'see' the entire board, I know it sounds stupid, but do you double check every piece ? And does that work in blitz too ?

I like blitz better, and I'm going to go for those training puzzles, but also wondering if you have extra advice for blitz games, I know the puzzles will help, but is there something different about that type of game, or is it just basic training put to a faster pace kind of thing ? Because I kind of 'know' that bullet games are not much strategy, lot of anticipation and action/reaction so wondering where blitz stands, or any general advice really ! about that type of game !

(For context, I play classics because it's easier to play at work lol)

Thanks a lot for the help guys btw

Sorry for the double post, just another quick question, how important is it to 'un-pin' pieces ? Not going to lie, I just did not care much about it.. lol, will try those pin practice as well

@Senpai-Noticed , the idea is this. Your opponent makes a move. Maybe you then respond, and suddenly, their bishop sweeps across the entire board and takes out your queen! You hadn't noticed. This happens to most players at some point, but players who see the whole board do not fall for this sort of thing. The key is to ask, after every move your opponent makes,
1) What is it doing?(What is it attacking, is it opening up another piece's attack.)
2) What is it not doing anymore?(Perhaps it was defending that knight, and that piece is vulnerable now.)
Other examples of not seeing the board would be getting checkmated because you missed the coordination of queen and bishop on a key pawn in your position, losing a piece because you move the piece that was defending it, and others.
Some of the puzzles will require you to use multiple pieces, and when you have to see each piece clearly, it will be harder for you to miss the bishop attacking the queen, etc. Hope that this helps.

On unpinning a piece. Generally it is very important. A pinned piece is vulnerable to being piled up on over and over by other pieces of your opponent's. If the piece is not pinned, you can simply move it, but pinned pieces cannot move, so the piece will be taken unless you can give adequate defense, which sometimes proves impossible, leading to loss of pieces, and or checkmate. They are also vulnerable to being attacked by pawns.