Why do i see things like walls move?

Ever since i can remember, ive had moments where i felt like the world was tilted sideways a bit. i would even fall out of my chair (like someone was tipping me off it) but everyone else was still sitting normally. I used to think it was an earthquake or something like that, but no one else seemed to notice. Now, more recently, I start seeing things like the ground or walls rippling like the surface of water. It gets all bumpy and it looks like it's breathing. Sometimes the ripples get as high as my knees. Does anyone know what this is? Thank you!