Peace be with you.
you asked: "You have several vivid visions. In the visions a person/entity tells you that s/he is God. When this happens you are awake and you have not deliberately ingested any drugs. During these visions you feel clear headed and peaceful. This person/entity is not frightening.
1. Do you accept this vision as from God? If so, why? "
Not yet, because the feeling of peace and clearheadedness does not instantly mean that the vision was from God. What was the vision? What was the purpose of the vision? Was it something pleasing to the flesh or beneficial for the spirit? Who's interest is the vision in? Is it in my best interests or that of the other person? Is the vision a message of comfort or is it reproof? Has someone sinned? Have I sinned? Why is this vision being brought to my attention? Does the vision "bear witness with my spirit?"
These things, and perhaps others, need to be known before one can discern if what was told or shown to them (in this case, the vision) originated from the Father, because many false prophets have entered into the world.
Peace to you,
Aaron