What Causes Dizziness And Headaches After Taking Z Pak For Ear Infection?

I was diagnosed with a middle ear infection 3 weeks ago. Dr. prescribed Z-pak and a steroid but about 2 weeks after taking the meds completely, the ear pain is back, the dizziness, headaches, vertigo and now I am having this sensation as if someone is pouring water down my skull in the middle back portion of my head.