Stargazing/Twirling "Disease?"?

It's me again, and I've been posting about my Zebra Finch who has been sick. She's already been taken to the vet and is currently on antibiotics. The vet said to bring her back in 2 weeks and it has only been 1 week. Although, I'm debating on taking her to the vet sooner due to some recent events. For the past couple of days, ever so often, my bird shakes her head back and forth quickly, in a bobble-head manner. I've done some research and it sounds alot like "Twirling/Stargazing." I was wondering if anyone had some more information on this or experienced this with their bird? Also, if you've read my other posts... you'd know that she has been refusing to drink the water with antibiotics in it, is it possible the bobble-head could be caused by dehydration?