Sorry for the wait..
Your kitty is experiencing what's called vestibular syndrome. This is a condition in which the balance center of the body is affected and the symptoms of disorientation and dizziness occur.
Vestibular syndrome is caused by problems in either the inner ear
cavity, the brain stem or the part of the brain called the cerebellum. There are multiple different conditions that can cause vestibular syndrome - infections, cancer, parasites and others. One of the most common causes of vestibular syndrome is an inner ear canal infection or a polyp residing in the inner ear canal.
It is usually possible to differentiate an inner ear versus a brain problem by physical and neurologic examination; once the differentiation is made, then some testing may be needed, but treatment may be easier, once it is known where the problem is.
Because vestibular syndrome causes quite a bit of discomfort and anxiety/fear, it's best to get this taken care of asap. If you don't have an emergency clinic within driving distance of where you are, I'd take your kitty to your vet tomorrow morning, but it's really best to have her seen tonight.
For now, if you have meclizine (Dramamine - over the counter medication for nausea and motion sickness for people), give her a 1/4 of a tablet by mouth - it may help with the dizziness.
Hope this helps; please let me know if you have any other questions or need clarification on the above information. Best of luck!