First you should realize something very positive: You are aware that you are very angry. Some people deny the extent of their anger, which does not help in cleansing oneself of it. After all, how can you reduce the anger if you are minimizing it? If you have a deep cut on your arm and you are afraid of infection, what do you do? If your fear freezes you to such an extent that you cannot clean the wound and apply an anti-biotic, then that fear is preventing healing. It is similar with injustices and anger. Fear of the anger is the problem more so than the anger is the problem.
Please keep in mind that you do have available to you a kind of cleansing agent, a kind of anti-biotic against toxic anger, and it is forgiveness. As you practice forgiveness, you will see that the anger diminishes. Even if it returns, you have forgiveness to help you once again. As you become better at forgiving, you will fear your negative emotions less because you now have at your disposal a powerful antidote to them. Enjoy the cleansing power of forgiveness.