I’ve been getting episodes of dizziness and ears ringing while

Patient: I’ve been getting episodes of dizziness and ears ringing while at work. Sometimes I’m feverish or nauseous and other times I get a flushed sensation right after my ears start ringing then I get disoriented. I went to the hospital after one of these episodes when I almost fainted and my blood tests were normal. They told me I was dehydrated and prescribed meclizine. I’m an active person and sting about a gallon of water per day and have upped that to 2 gallons since my visit but the symptoms haven’t subsided. What else may be the cause?

Doctor: