best response to 1.e4 d5 ?

what is the best response to 1. e4 d5 2.exd5 Qxd5...as white,i always struggle against this opening.

it depends on the game

Nc3, for me.  I love it when my opponent plays this opening as Black because it generally affords White a lead in development.  Nf3 is ok too, but I prefer making the Queen move again right away.

3 Nc3 is best. The opening is fine for both players BUT they have to know the main ideas. 3...Qa5 is most common followed by 4. Bd2. 3...Qd6 has been getting more popular but White should just develop normally. I have played both sides of this opening many times

Knight on c3 so he got to move his queen

and later your next Knight on f3 and develop bishop and castle . . . easy in theory

challenge me and ill play that

Nc3 , Nf3 and e4 should be your next moves... you then have got open diagonals for your bishops and are ready to castle (after bringing your bishop out)

in fact, that kind of defense for blacks is a kind of risky,its like gamble for blacks, if white doesnt know that defense,they can surprise, but if know it, the black Queen will be jumping around a lot of time losing time, and the best response Qxd5 is Nc3, then you have to open diagonals for yours bishops and go on.....

This defense is not risky for Black but fairly solid. White wants to delay Nf3 so that if Black posts his Bishop on f5 he has the option of kicking it with g4.

4.Bd2 is not a legal move in this position.

Chess

I play the Anderssen Var 3...Qa5 (the main line) of the Center Counter Defense. (that's Scandinavian to all you Euro players..

At my level... So far so good. That said, I find the lack of GM's using it other than blitz somewhat concerning...

That's why I chose to play it - because I always lost to it (you struggled, I just lost all the games). The answer is somewhat unnatural:

You can also play the Leonhardt Gambit, a Nakamura favorite:

Here is how Kasparov played against Anand in their PCA World Championship Match:
https://www.chessgames.com/perl/chessgame?gid=1018629

After 1 e4 d5 2 exd5 Qxd5 3 Nc3 Qa5 4 d4 Nf6 5 Nf3 the move 5...Bf5 is what is used in the repertoire book The Scandinavian for Club Players, so 5...Bf5 is what I play since I use that book. 5...Bg4 looks playable but 5...Bf5 scores better in databases.

After 5 Nf3 Bf5 6 Bc4 the modern 6...e6 is considered the most flexible. It saves the c6 square for the knight, plus black can reply to 7 Bd2 with 7...Bb4.