Trading is nothing more than a long, random statistical run. An experienced trader knows that even if he is in a losing streak right now, as long as he sticks to his already approved trading plan, he will come out a winner in the long run. This is why becoming angry is pointless. In fact, it is worse than pointless, because heated emotions often lead to poor decisions in subsequent trades. In such situations, a cloud of emotions takes possession of the trader, commandeers his brain, and disrupts his trading.
Remain dispassionate. Make it your goal to achieve a cool and calm demeanor. This way you can stay impartial towards your trading without letting your emotions influence your decisions.