This might sound weird and it’s hard to explain, but sometimes just before I’m falling asleep I get this feeling like my body is changing sizes. That doesn’t really describe it very well. It’s like one second I feel like I’m this huge giant then the next I feel incredibly small. Like I’m expanding and shrinking. Just wanted to know if this was common or if it’s just a weird personal thing!
Hi Zzz (etz), welcome to the forum!
Its not somehting very uncommon I guess, since I have that feeling too sometimes. Pretty cool stuff 
.
I’ve had these sensations ever since I was about 4 years old. They’re so strange; it’s almost as if the world is reshuffling its space dimensions. I wonder what causes it… I usually get them nowadays when I’m doing some meditative practice while lying in bed.
Used to feel that as a kid. I feel it sometimes still, but it’s rare.
Don’t know what it is. But it’s so real 
I have those feelings too, but i thought it was only me. Sometimes my arms shrink, then get really big. Sometimes its only one arm.
I never felt exactly yhat you’re describing, but do I sometimes feel like I’m being tilted from side to side just before I fall asleep.
I used to feel that all the time as a kid! Never felt the body changing thing though.
I have a feeling pretty much like this. Sometimes I lay there and feel myself getting shorter and shorter. Other times I feel like i’m getting realy tall and expect my head to hit the headboard and my feet to start danggling over the edge of the bed. 
I’d say it’s pretty common.
I haven’t had that, but I’ve had weird floating sensations before. 