Controlling emotions is usually seen as next to impossible, but in reality you CAN take control, although it is by no means easy and takes a lot o time to master.
One of the best ways to start off is to learn not to get your emotions involved in ANY aspect of your life and first of all try not to react in any way even when something good happens. Having mastered that, it will be way easier to keep calm with some negative events... This is like a general idea

Works for me!