Talk to Immunologist on Dizziness

My daughter is feeling dizzy for over a week now. We have been to different physicians and ENT and couldn’t figure out anything. Her ears are fine, her blood test is ok. Her diet is normal. can’t figure out what’s the issue. She is having frequent episodes of dizziness. Mostly when she get up but some time even when she is walking or just sitting. To rule out dehydration we used fluids too including electrolytes but nothing is working. She had stemetil for few days but no use . Please suggest what’s wrong. Thanks