I dealt with this kind of thing for years growing up, and for the most part grown out of it but it can still strike me out of nowhere.
The feelings of the walls of the room suddenly racing away from you, or the feeling that your hands are suddenly 10x as big and everything you touch is tiny, are terrifying for a growing kid. Heck even talking about it now tingles those fears just a bit, but now I can for the most part logic myself out of it.
I slept with a light on in my room for many years, that was the only thing that helped.
Interesting. I never knew there was a name for this phenomena. It happened to me every now and then as a kid, too, usually when I was sick and in bed. In my case, it made me feel vertigo, like size scales were shifting around so fast I'd lose my balance and fall over, stuff like that, but I don't remember any particular fear reaction per se, other than feeling kind of gross when it happened. I found that dim light (like a nightlight in a child's bedroom, with long shadows) was the worst trigger, and either bright light or complete darkness helped avoid it.