Fainting and Dizziness 21 weeks

I was wondering if any of you experienced fainting and dizziness during your pregnancy? About a month ago I started having dizziness and just fainted about a week ago . I can't walk over 5 minutes or the room feels like it's spinning. All of my blood work came back fine. I have been off work for a week now scared to drive anywhere. Dr found some fluid in my ear and but my on Zyrtec but I am still dizzy I see the Dr again today he may send me to a ENT specialist . I have a past history of fainting but not the dizziness.