Need to vent and also get advice

I have a history of getting shitty doctors while pregnant and it seems like it's happening again....I'm having a difficult time with my current doctor I went in to the er about a week ago and they told me to have my doctor send a referral to get an ultrasound at 20 weeks to make sure everything with the baby is ok. So I called Friday they said she was in and that they'd give her the message and I should be able to go in by Saturday. I called back Saturday to try and schedule the appointment they didn't receive the referral so I called my doctor office and asked again. they said the same thing so I figured I'd give it a day in case she was super busy or something. so I tried to make the appointment again today but I was told today they still don't have the referral. So I call my doctor office and they say she's in the office we should have an answer for you today. they put me on hold for 30 minutes and then they said oh she hasn't been in since Friday it's like she's avoiding me. When I first started seeing her I told her I have major back issues and need a referral to a chiropractor but she wants me to do core exercises instead of going to a chiropractor because she doesn't believe in it even though I have had one going on 6 years. I had to change to this doctor due to my other one leaving so I asked for them to have another doctor send my referral so I can go in cause I've been in so much pain an I'm worried. I also shouldn't have to keep trying to get a referral to get another ultrasound when I already was at the er and I have a history of miscarriage it's like she doesn't care. I'm going to go in to the doctor office hopefully tomorrow to get this straightened out but Ugh should I just change my doctor again