I'm a pro at feeling angry ! I have been angry my whole life. Also, like you, I am far too trusting and a softy emotionally, which I chalk up to being raised by TV shows where I totally lost myself in some kind of fantasy reality "Leave it to Beaver" world.

To deal with my anger I usually rely on the following:

1. shadow boxing - I've watched YouTube videos on how to throw a good punch, and I am constantly practicing my moves by punching the air. best done when no one is watching, because it will make you look a little nuts.
2. road rage - take a nice drive, you have no where to go but you feel in such a big hurry. The first person to cut me off or go too slow gets it. Pull beside their car screaming obscenities, this will get your adrenaline going. Most likely they will react in such a way that either incites you more or makes you feel foolish, either way eventually you will feel foolish and this will calm you down.
3. screaming - scream in a closet, in a pillow, or if you are really going over the edge scream in someone's face, again do this until you feel foolish.
4. get physical - if you can play contact sports, that is ideal. If you cant make sure not to attack anyone as it is illegal. This still won't stop you from getting physical, go for a walk/jog, make it arduous so that the anger is exhausted out of you. Best of all, take a self defense class where you can practice punching a guy in a padded suit, no one will question this.
5. throw things - Nothing says anger like when two people start throwing plates and breaking things in a fit of uncontrolled rage. Best option is to wait for no one to be around, grab a couple dishes you don't like and make sure to break them in a place it won't do damage to other stuff. It's good to combine screaming with dish breaking. Channel your rage into the plate, scream and start smashing stupid dishes. Chances are after a few you will collapse in tears and feel quite foolish. If you like your stuff and don't want to break anything, throw rocks outside.
6. fantasy - fantasize about what karma awaits the one who angered you, as a last resort plot revenge.

(these are just my tools, I am not a therapist)