Hi, The swimming sensation would be called vertigo and there are different possible causes. Most commonly it is related to the inner ear. The inner ear causes are (1) vestibular neuronitis - there may be a recent viral infection. Vertigo can last for hours at a time. The use of certain meds for a short period of time can help eg Dramamine, Benadryl, valium etc (2) BPPV (benign paroxysmal positional vertigo)- episodes last seconds to minutes, occur with certain head positions. There is a manoeuvre called Epley that can help with it (3) Meniere s disease- associated with abnormal noises in the ear (buzzing, ringing etc), occasionally hearing loss- Low salt diet and the use of diuretics would help. You should consider seeing either ENT or a neurologist. Hope I have answered your query. Let me know if I can assist you further. Take care Regards, Dr Michelle Gibson James, General & Family Physician