My daughter has been dizzy for 3 days now already on zpack and no better but having more symptoms what should I do?

Go back to doctor. I would take her back to the doctor for re evaluation.
Hard to know. Is her dizziness light headed or the sensation of spinning or moving. If its feeling like moving it could be viral labyrinthitis which is best treated by high dose steroids. If it is lightheaded she might be dehydrated. You need to take her to a doctor for an evaluation and treatment.