“Thank you for posting so that I can see a neurologist and have knowledge”.
@ Susie:
I would start with a regular veterinarian, find one close to home, ask dog owners in your community who they go to/recommend.
She needs a senior workup, labs and exam to begin with.
What you describe sounds neurological, it is not recommended to give a dog with a neurological condition any vaccine, so just decline and remind them she is a senior and she is not medically stable if they bring it up.
Do not give over the counter meds or supplements to your pet unless recommended by a veterinarian that has examined her. You have no idea what you are treating and could make the situation worse. Especially with medications that are intended for humans.
First thing is to get her diagnosed by a veterinarian and then evaluate the treatment options that are presented. I wouldn’t make any diet changes right now either.
