This is actually a more common question than you might imagine. Anger is uncomfortable for us and when it is intense, it can be unhealthy for us. Something to keep in mind is this: As you continually forgive, I mean truly persist, then the anger will diminish. It will move to a more healthy level. A key is for you to be in control of your anger rather than the anger to be in control of you. The emotion of anger may be with you for a long time, but the emotion of unhealthy anger will not be. For now, let us make this the goal—not to be entirely rid of the anger but to persist in forgiving until the anger is manageable. When anger comes to visit unexpectedly a week or a month from now, be prepared to forgive again. The more we practice forgiveness, the more quickly we actually forgive. So, please be encouraged.
For additional information, see The Four Phases of Forgiveness.