Can I get another doctor?

Today I ped out in the shower. I am 27w 6d pregnant. Everything in my pregnancy has been fine and today it all went down hill. I went to the ER and they sent me up to Labor and Delivery. My regular OB came in and said that dizzy spells are normal for me. Sometimes I get light headed when standing up really fast but that is it. She watched the baby for about two hours and sent me home. Do you think she was being rude by saying that it was a normal thing for me even though I never ped out before? Also she did not even look at me for anything. They did not take blood work or anything. I went back to the ER on my own and found I was severly dehydrated. This could have really harmed the baby. Is it to late to switch to another doctor who is not only concerned about the baby but also my health?