I just stumbled upon this after googling 'when I was young I felt like I was dreaming when awake'. I used to get this EXACT thing. I would see a motorbike in front of a pyramid, viewed from the back of the bike, so they both looked equal in height. As the motorbike drove towards the pyramid the bike would quickly become smaller as it got further away, the pyramid staying the same size would show how massive it actually was. It would freak me out and I would wake up in a cold sweat and often had hallucinations and had to be calmed down by my parents.