When we lose our money in gambling, we will not become emotional because we know that losing our money in gambling is the risks of playing gambling.
Somehow, when we lose we get even more emotional. In some cases, when you are losing your money you are also losing your cool. You get irrational and you lose all logic. You just want to win and that’s understandable but you need to fall back and keep all emotions away from the game.
To handle this from before gambling is to use money that you are ready to lose, have good self-control by basing yourself that victory is a luck that you don't have to get every time, defeat is clear evidence that the tone will not get victory easily.
With this I think you will be much better at controlling your emotions or feelings about gambling, because the average case of people losing control of their emotions is because they often use money that is not ready to lose, and make winning something you have to get so that your impulsiveness arises because your emotions are triggered.