Weird shrinking experience?

[BellaBonanza]

So I'm 13 and I just now wanted to know about this strange experince I have been having for as long as I could remember. Sometimes it happens while I am awake and alone in my room and other times I am in the process of falling asleep (already laying in bed with eyes closed). I know this may sound quite weird but I always see Spongebob characters appear and usually a ball. The backround is white and these objects become really small and I feel small myself and really uncomfortable and insecure. I am fully aware that it is happening both awake and while asleep but I don't know why and what caused it/how to stop it. The senation feels like it happens for around 30 seconds to a minute. No, I don't secretly smoke or do any type of drugs. I usually stay up late because of school and fall asleep around 2 or 3. I really do hope you guys have an idea of what I am saying because it's really hard to describe