My dog keeps holding her head down when she walks around. She usually holds it up and I notice her kind of limping it seems like she is sad?

Placing a question mark after a statement does not a question make.

Any behavioral change warrants a visit to a vet to rule out any possible medical issues.

So......you see a major change in your dog's behavior and signs of pain but won't take the thing to the vet? How bad does it have to get before you recognize a problem? Do you REALLY have to be told to do the vet visit?

Sounds like something is wrong and that she's in pain. I suggest you take her to the vet.

sounds like a neurological issue.

Take her to the vet, something is wrong.

Not sad but she is in PAIN.