Hello, Dizziness is non-specific symptoms, so it can be from many different causes. Sinusitis is one of the likely causes for your dizziness as well as affecting your ear symptoms. However, the fact that you completed antibiotic treatment ruled out this as a cause at this point. Labyrinthitis which is an inner ear disorder is another highly likely cause for your current symptoms, especially with your current ear symptoms. If you had recent upper respiratory symptoms, this supports Labyrinthitis even further. It can cause balance disorder such as vertigo and dizziness in addition to fullness in ears. They are usually from a viral cause, so you do not need to take antibiotic treatment and it gets better on its own over the course. The other likely causes include benign positional vertigo or Orthostatic hypotension which I cannot rule out either. If your dizziness continues to be persistent or get worse, please follow up with your doctor or urgent care so they can check your blood pressure and another physical exam to rule out each condition and get appropriate medication to control dizziness. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr Katie Lee, General & Family Physician