I get very emotional too and because im very opinionated, when people dont agree with me or i find that we have differences (not only in opinion but in morals too), i get into a right state. When i get fussed up about things, i used to just let it all out there and then and people used to tell me to just calm down and stop being so emotional, so now ive learnt to keep it in me and go home and let it all out there by myself. Sounds incredibly scizophrenic but i talk to myself, and hearing my thoughts helps to decipher whether im right or wrong (or just too over the top) about that thing.. Writing down what you're feeling also helps. But its better, if you get pissed off or whatever, not to let yourself go there and then.. keep it in, trust me its better. And then when you're alone, let it all out!