@Mrs feegs I've had a couple of pigs that this has happened too. Normal practice is to treat as an infection first.
Which antibiotics did you get? If it's Baytril and you don't see a positive result in a few days go back to the vet and ask for Zithromax.
If you try the Zithromax and don't see any positive results go back again. It could be a neurological problem. The downside to that is that it could be so many different things causing it so it can be quite hard to find out what it is exactly and might take a bit of trial and error.
We tried Panacur on my last pig when we ruled out infection. We wanted to see if it were fungal.
Please keep us updated. I hope your little one gets better soon.