Although the late Lewis Smedes, in his book, Forgive and Forget, said that it is all right to forgive God because God is mightier than our anger, I disagree with my highly respected colleague on this point. As a Christian, you see God as all holy and pure, beyond injustice. If you start to forgive God, then you are saying that there is imperfection there, or worse, even injustice. An all-holy God cannot be unjust and so to forgive is to diminish the attributes of God.
Anger can be natural, but at what are you angry? Are you angry at circumstances in this imperfect world? Are you angry at how people in the world have treated you? I urge you to try to work on acceptance of what is happening to you and to forgive persons who are unjust. You could go to God and ask for help in bearing your pain as you walk through this time of challenge. Please keep in mind that as you walk this path of pain now, you could be strengthened in the near future.