I did a bit of research into AP for the past couple years or so. I would say that it'd fall into that category.

Astral Projection isn't necessarily entry into a world, but rather, the sensation of the separation of consciousness from the body. Your experience runs many parallels with these experiences. That is - vibrations, the sensation of leaving the body, and the creation of matter from focus. I've read similar experiences where the subject has entered a sort of "training space", and is able to create objects from their mind. (One person in particular summoned a few family members.)

It sounds like Astral Projection. Is Astral Projection actually Astral Projection? I don't know, and I don't intend to get involved in that debate. But, it does happen. And it sounds like that might be the case with your experience.