Sounds like you did it all right and hit the spinning perfectly - how long did it take you to reach this stage?

I think if you focus too hard you can lose it - I would recommend slowing the spinning if you can, try to open your eyes, don't worry you wont open your actual eyes. When you do try emagine what you want to be looking at. When you open your eyes this will offer you the stability to stop the spinning completely and be lucid