How do I control my temper im a very happy person for the most part and some things just set me off ?

like the other day I get off work and my girlfriend starts telling me stuff that doesn't really make sense and for some reason I hate stupid stuff like that. And I started lashing out on her and got her real upset and I don't like getting mad. Sometimes I wonder if I can control my anger but I think all my anger comes from all the stuff from my childhood. Wat should I do