the other thing is liver shunt as they head press and walk in circles - this sounds more like what you are describing - what protein percentage are you feeding -
Portosystemic Shunt (Hepatic Shunt) in Dogs
If this was my dog i would get to vet and have cbc panel and bile acids done on monday to first see if liver shunt and then if not i would see a neurologist. I would go in on monday on a 12 hr fast and have them do the cbc panel and the pre-bile acid then bring food with you and do the post get that all done at same time so you can figure this out
how old is your dog?
if it is liver issue then hopefully vet will put your dog on hill's L/D ,give you lactulose as that will help with toxins and do milk thistle and sam-e or give you (denamrin which is milk thistle and sam-e combined)
read those two links and see if either of these sounds like what is going on