score:0
What you are having difficulty grokking is a concept known as the "Trinity." The historically correct definition of the Trinity is that God is "three persons in one."
When Jesus says, "I and the Father are One" (in John), he is claiming that he is God. Historically, God the Father, Jesus (God the Son), and the Holy Spirit are all considered the three persons of the Trinity. They are all equal, they are distinct, and yet they are all the same.
This link explains the relationship as well as any :)
Don't worry, its a difficult concept, but it is the basis of Nicene Christianity's understanding of how God exists.