Responding to 1.d4 is a matter of taste. Personally I almost exclusively reply with 1. ...Nf6 since I am somewhat a King's Indian(KID) specialist, an opening that is not recommended for beginners because of the sheer complexity and different paths your opponent can steer the game. On the other hand 1.d4 d5 usually leads to more or less the same kind of position, expect to see IQP-type games often. From how you play your games, I have a feeling you should aim to play against the IQP.
why do i lose when someone plays d4 ?

@BobbyTalparov I'm new to chess strategy and tactics and I've never read any book on chess. I was going to read "The Amature's mind" from today . After finish it I'll read " logical chess move by move " I dont even know whether it is a good book or not , If you know any better book for an intermediate like me , please do suggest

@BobbyTalparov I'm new to chess strategy and tactics and I've never read any book on chess. I was going to read "The Amature's mind" from today . After finish it I'll read " logical chess move by move " I dont even know whether it is a good book or not , If you know any better book for an intermediate like me , please do suggest
Start with a book like:
Logical chess move by move - Explains the "why" behind each move.
Silmans Complete Endgame Course - Endings.
1001 Chess Exercises For Beginners - Tactics.

@notmtwain But when white plays 1.d4 2.c4 , i don't know what to do
What black can do against those two moves accounts for practically half of all chess opening theory
So needless to say, there are many options.
But here is a very standard sort of setup (it's not just for beginners, all levels of players use this)
These can be your first 4 moves against many things white does in 1.d4 openings. You can pretty much play them on autopilot and not worry about what white is doing.
Other than castling, your goal (in the vast majority of positions like these) is to eventually play 1 of 2 things.
1) the move pawn to c5
2) Instead of that, you can play pawn to c6 and try to play e5
In most positions if you're not playing either c5 or e5, then something went wrong for you. (These moves are called pawn breaks, and open lines for your pieces).
On move 5 or 6 you're not typically playing e5 or c5 already. I'm just telling you that so you don't waste time with moves like Ne4 (which is literally a waste of tempo in most positions if you're playing it early). Also you wont play typically bad moves like Nc6 when the pawn is still on c7 (this is not a losing move but makes the game less clear).
So lets look at some typical ways black finishes development and plays either c5 or e5

Note that you seem to be ok with opening principles, but note that a National Master who gave a talk to my strong (3rd place state trophy) high school chess club surprised my players when asked what his favorite opening was: "Whatever one that gets me to a playable middlegame."
The point was that you need to play openings that lead to middlegame strategies and tactics you can work with. For example, if you play the Slav Defense against 1 d4, surely know that an idea behind the opening is to get your QB to f5 or g4 before ...e6 blocks it in. But you also need to know that ...c5 is often how you begin a counterattack and you need to explore, perhaps with the help of an engine like those in the freeware Lucas Chess as well as going over master games, what KIND of attack proceeds after ...c5 and after other moves as well.
This is also true of QGD, King's Indian, etc.: gain an idea of what you might most frequently do or threaten to do in the middlegame
Personally, on the other side of the board, I've been experimenting with 1 d4, specifically the London System which is the mirror-image of the Slav Defense with a move in hand, and I'm not doing as well with 1 d4 as I do with 1 e4 - and it's because I'm just becoming familiar with the middlegame positions that are possible.

it starts like 1.d4 d5 (cuz i prefer symmetric games) 2.c4 Nc6 3.Bf4 Nf6(i don't know how to reply to this so i focus on devolopment) and then after a couple of moves i always lose a piece
In Queen's Pawn openings, it's not usually a good idea to block your c-Pawn.
So as Black, after 1. d4 d5 2. c4 you probably shouldn't play 2. ... Nc6. That Knight usually ends up on d7, later on.
Try 2. ... e6 or 2. ... c6 instead (or even 2. ... dxc4 followed a few moves later by ... c5).

Oh, and I didn't really mention it, but I'm trying to give a general blueprint for what black is thinking. This is something you can use in many different openings after d4 d5 regardless of the specific move order or opening and it should help you choose how to develop your pieces (to engineer your pawn break).

For example, oh no, white is playing something different!
No problem, the general setup is still very reasonable, and you'll still be finishing development with the goal of achieving an eventual pawn break, either e5 or c5.

Yes, the "Orthodox formation" is perfectly playable against a wide range of White's openings.
For example:

Maybe similarly, against hypermodern stuff you can almost play a london-type setup against anything and be comfortable.
So c6-d5-e6 with the bishop on f5.

@fisheyedfools and @BobbyTalparov thanks , I've started learning from "logical chess move by move" and I'm gonna read all of those books suggested...

@fisheyedfools and @BobbyTalparov thanks , I've started learning from "logical chess move by move" and I'm gonna read all of those books suggested...
Dont READ those books, STUDY them.
Stick with 1 book, until you have thouroughly studied it, before going on to another book.

@notmtwain But when white plays 1.d4 2.c4 , i don't know what to do
What black can do against those two moves accounts for practically half of all chess opening theory
So needless to say, there are many options.
But here is a very standard sort of setup (it's not just for beginners, all levels of players use this)
These can be your first 4 moves against many things white does in 1.d4 openings. You can pretty much play them on autopilot and not worry about what white is doing.
Other than castling, your goal (in the vast majority of positions like these) is to eventually play 1 of 2 things.
1) the move pawn to c5
2) Instead of that, you can play pawn to c6 and try to play e5
In most positions if you're not playing either c5 or e5, then something went wrong for you. (These moves are called pawn breaks, and open lines for your pieces).
On move 5 or 6 you're not typically playing e5 or c5 already. I'm just telling you that so you don't waste time with moves like Ne4 (which is literally a waste of tempo in most positions if you're playing it early). Also you wont play typically bad moves like Nc6 when the pawn is still on c7 (this is not a losing move but makes the game less clear).
So lets look at some typical ways black finishes development and plays either c5 or e5

@fisheyedfools and @BobbyTalparov thanks , I've started learning from "logical chess move by move" and I'm gonna read all of those books suggested...
Dont READ those books, STUDY them.
Stick with 1 book, until you have thouroughly studied it, before going on to another book.
@notmtwain But when white plays 1.d4 2.c4 , i don't know what to do
Ask yourself, "What does c4 do for him?" FishEyed already gave you a good starting point, but I would also recommend looking up some classical Queen's Gambit Declined games (there are several in "Logical Chess Move by Move" and "The most Instructive Games of Chess Ever Played"). These will help give you an idea of what you should be looking for.
@OP
Play over the Capablanca vs. Alekhine match, and youll never want to play the QG ever again.