How long does a sinus infection make u dizzy?

6 weeks??: Sinusitis, as well as many viruses, can cause a labyrinthitis, that results in dizziness. This can last sometimes as long as 6 weeks, with symptoms sometimes severe enough that people look drunk when they try to walk or have nausea with it like being seasick! it is important to see your doctor, to rule out something else & diagnose you, and there are some medications that can help the symptoms.