Switching OBs

Has anyone switched OBs in their third trimester? I'm 28 weeks and my OB is driving me nuts. Back in April they said that I had blood in my urine and it was most likely just a kidney stone that would pass so I just went on for a while until 2 weeks ago I started having bad pains and went to ER and it was a kidney stone to big to pass. I had to wait a week to make appointment with a urologist because she was on vacation but the day I called I got in to see her and got admitted into hospital that night. Urologist did a test and I have 2 kidney stones that are to big to pass and could possibly block my organs causing more problems. She was freaking out because I can barely eat and when I do it comes back up and I have been in a lot of pain. The OB just wanted to send me home without even talking to me or anything. So I am really thinking about switching OBs because of this. I just dont know how big of a struggle it will be switching OBs in 3rd trimester.