So...it doesn't sound like anybody has told you why you are getting these symptoms? Stress is one of my key factors for headaches, but the vertigo and the inner ear related stuff sounds like something that could affect that too.

On a side note, the over the counter Madam Pearls Cough Syrup used to have codeine until about 5 years ago. It's imported from Hong Kong; doesn't work as well now that they changed the formulation laugh.