I dreamed about a person who is about the same height as me, but in the dream I looked back at him and he seemed very tall!!! I don't remember much more, but when I woke up I felt a sense of calm or peace. What does it mean?

Do you know this person in real life? Do you like this person? Did this person (if you don't know him in reality) remind you of someone in authority, perhaps a Christ-like figure?

The previous person who commented has good insight, as there are many factors. But it seems whoever this person may be, personally or as an archetypal figure, his "tallness" reflects your understanding that he is, like a father figure, protective or understanding, a strong and supportive resource. Was he "following" you, in a protective way?