I had something possibly similar as a child. Sometimes, I'd have a feeling of partial-spinning...a feeling of turning maybe 20° to the right, then 20° to the left. It felt as if it went on for a minute or so, getting progressively slower and fading away. All I remember was that the pediatrician told my mother that it was fairly common and I'd likely grow out of it. And it was fun in a way.

It still happens, maybe once every few years, if I get overtired. An acupuncturist once told me that it's just the body rebalancing energy when the body is at rest.