Did you have control over the spinning in the gown?

Physically, it could be something akin to vertigo in your sleep. Check yourself out for ear infections and the like, as your equilibrium might be thrown off by fluids. The offset equilibrium might be to blame for the nausea and the spinning sensation.

Other than that, the symbolic meaning is akin to yourself or your life being out of control, and you being unable to regain said control. What in your life seems to be going awry and what are you doing to reign it in? How is it failing? What needs to happen for it to return to being under control? How can you obtain these goals productively?