Grace has had a bout of vestibulitis--but luckily is just a wee little thing of about 35 lbs, so it was easier on her human folk. She seemed to feel dizzy and did a lot of staggering--and she had that look that told us she was feeling at least odd, if not uncomfortable. We just waited it out. It can take a fairly long time for the symptoms to resolve, though in Grace's case the stumbling disappeared quite quickly (within a week or so, as I recall). The head tilt took almost a year to resolve, though.
I hope Timber starts improving quickly! Is she still shaking? Poor girl. Give her a big hug for me!