sometimes its good to have a cry.
How to control your emotions?
Consider writing things out in a journal in order to help rationalize/catagotize your thoughts.
There's a Cherokee teaching that we all have within us two wolves; one is good, the other bad. The two wolves fight and the winner will be the one we feed best.
Emotions are like that. If you dwell on the negative you are feeding the weaker side of your personality' if you focus on the positive you become strong.