Should i take her to the Dr AGAIN?

My daughter has been coughing for about 2 weeks. Was seen twice at her pediatrician who said its just drainage from her cold. Well for the past 2 days she's been coughing so hard she's throwing up. It seems a lot better when she is relaxing, but as soon as she starts moving around she's going into these coughing fits. I called the doc tonight, who said bring her in to the afterhours clinic if im concerned...well i am, but she was already there twice, i dont want to bring her again, to be told the same thing...does drainage from a cold cause coughing fits like that? Would you bring your child in for a 3rd time? She has had a low grade fever for about a week.