A. walking around in circle is usually a vestibular sign - meaning it comes from either the brain or the inner ear. If his head doesn't tilt to one side, a brain condition would make more sense. It would also explain the difficulty eating.
Unfortunately this is not good news, you should go to the vet for a neurological exam. The only way to confirm a brain lesion/tumor is a CT scan. If he is insured it will be covered.
Your account has been reactivated.