ACIM reminds us that everything in the world is an idea and they are all unreal. Because they are all equally unreal, there are no conflicting ideas. Yet there is an actual real idea behind them, called Christ. You are an idea of the Mind of God. Christ lives forever in the Mind of God and has not left the Source. That is what you are waking up to. That is where all this is going to: an endless mind being an idea in the Mind of God. That is Oneness.
Any time your mind goes into any kind of upset, it indicates that there is something to forgive. Ultimately you are forgiving the subject/object split, the idea that there is a perceiver and the perceived. Releasing the belief in the ego is how you forgive yourself.
Whatever or whoever you believe you are in this world does not really matter. The Holy Spirit is going to be there as your friend to help your mind keep exchanging concepts and to take you higher and higher in consciousness until you get to the top. You have to give up all judgments. How is this accomplished? Through miracles! In Oneness there is nothing to forgive.