An analogy is when you're comparing two things. A metaphor is a type of figurative language where you're applying an abstract idea or concept to an object. A simile is the same thing as a metaphor except it uses the words "like" or "as" when applying the abstraction to an object.

So the body bubble would be an analogy. The type of dissociation I feel is like being inside of a body bubble. They are two similar types of experiences. I'm having trouble coming up with a good metaphor, probably because I feel like I'm inside a body bubble.