Kings pawn opening St. George Defence B00

I was playing white. What do I play against:

1.e4 a6 2.d3 d5

I have no idea what to play as, capturing destroys my pawn center.

Should I just add some defence to my "e" pawn?

If your opponent is going to give you the center, take it 2.d4

 Yes 2. d4 is better than 2. d3. 

What about Sicilians defence ?

then d3?

Anyone at your level is NOT going to know how to play the Sicilian.  At your level, openings are the last thing you should be studying.

There's nothing wrong with 2. d3, intending to play a King's Indian Attack formation in which Black's 1. ... a6 move is just a wasted tempo. After 1. e4 a6 2. d3 d5 I would play 3. Nbd2 then g3, Bg2 etc.

https://www.chess.com/livechess/game?id=2699464405

This is the OP's last game.  Opengings are the last thing he should be wasting study time on.

Yea I was in a rush in that game  

Here you lost in 7 moves against a 700 player.  Why do you want to waste your time on openings?

https://www.chess.com/livechess/game?id=2699541851

I am trying to learn everything mainly how to prevent blunders

You have played 250 blitz games.

41 bullet games.

0...as in ZERO games longer than 10 minutes.  

How do you expect to improve when all youre playing is blitz, and bullet?

If youre serious about improvement:

Forget about learning opeings, and follow opening principles.

STOP playing blitz, and bullet, and play games of at least 30 minutes, and preferably longer.

Opening Principles:
1. Control the center squares – d4-e4-d5-e5
2. Develop your minor pieces toward the center – piece activity is the key
3. Castle
4. Connect your rooks
Tactics…tactics…tactics…

Pre Move Checklist:
1. Make sure all your pieces are safe. 
2. Look for forcing move: Checks, captures, threats. You want to look at ALL forcing moves (even the bad ones) this will force you look at, and see the entire board. 
3. If there are no forcing moves, you then want to remove any of your opponent’s pieces from your side of the board. 
4. If your opponent doesn’t have any of his pieces on your side of the board, then you want to improve the position of your least active piece. 
5. After each move by your opponent, ask yourself: “What is my opponent trying to do?”

Wait I have played bullet?

Also sorry correct me if I am wrong but there is no point in checking if it does not put them in a worst position or put yourself in a better position 

Also I never really thought of connecting the rooks so thanks!!

Wow I am actually a lot better at 30 minutes!!!

Thanks!