I have really fast daydreams, like a million different images or videos are shown to me in a second. These are uncontrollable, and only happen if I daydream for about 25 minutes straight, which is what I like doing. The speed grows faster as I continue into my daydreams. When it gets too fast, I start getting a headache so I stop daydreaming at this time. Why, and how, is this happening?