It may be because you have experienced so much in the past and that's what you do when something like that happens.
I would suggest you that you get an object that calms you down.. something small that can fit in your pocket, like a soft hanky, stress relieve ball, an old fancy coin, something that you like. If you get mad- feel the soft materials with the tips of your fingers or start squeezing the stress ball, flip the coin or spin it on a table.
I hope this helps you kickstart an idea.
Sounds like me at your age. I have bipolar and borderline personality disorder. Once I was walking down the street and beat the crap out of my own face. I punched it dozens of times until my hand and face were black. I woke up strapped to a bed in a mental hospital and had to stay a week.
You've told yourself too long that you can't control them!
Has anyone ever punched you back?
You cannot control feelings; you can only be aware of your feelings and in touch with them and honest to yourself about what you feel. What you CAN control is your actions. That needs to be your focus. The difference is between childish impulsivity and adult self-control. Children have no thinking spaces between their feelings and their actions; that is impulsivity. Focus on acknowledging your feelings but controlling your actions.
For more clear information on what it means to be an emotionally mature person, go to the website for the Maryland Institute and look up this article: The Characteristics of Emotional Maturity.