How to stop fried liver attack?

People play this against me, the fried liver attack. What move should i play?Sometimes I can't castle because i play other moves

Good question!

As black, simply castling is the best response. If the bishop and knight decide to trade themselves for a rook and a pawn, black has the advantage since two minor peices are generally superior to a rook and a pawn, especially in the opening. This becomes evident when you think about how many squares each can cover: a bishop and knight can cover far more than a rook and a pawn. After castling, white's knight is stranded too far forward, and very likely to move back several moves later.

5: Nc3 is an interesting move by white in your diagram. Most white players will play 5: O-O or 5: Nxf7 

5: Bxf7+ is uncomfortable for white because after the king moves he has a hanging bishop (attacked once defended once) guarded by an easily kicked defender.

I prefer to play this line... 

Only because in your variation, after Bc5, instead of Nc3, Nxf7 is much better and winning. 

The Fried Liver Attack has been refuted:

https://www.chess.com/forum/view/chess-openings/my-refutation-to-the-fried-liver