Hi Manni
I'm 9 weeks, just had an appointment with nurse who will be my assigned carer/midwife equivalent where I am here in the USA (they don't seem to call them midwives). I had to see her as I had a scan and bleeding. Long story short, it was an horrendous experience, instead of talking me through my scan results (the sonographer wouldn't, weird hospital policy here), she said, yep all fine, now let's talk about your 'advanced maternal age' and genetic counselling and spent the next 25 mins aggressively pushing me to go for this test and that, despite me saying I wouldn't do anything no matter what the results might be. She didn't want to listen, was aggressive to the point of offensive. 
I came away so distraught, cried all the way home, I texted my DH who come home from work straight away. We absolutely will be changing dr's as I think they might all be like this. Haven't met the consultant she works for but don't feel good about their ethics.
Don't let her intimidate you, be rude or whatever / however she behaves that is making you feel bad. Absolutely change if you are feeling vunerable or pissed off with her and bugger if she is offended by your change!
Can't unfortunately claim to know the process for changing...say to the surgery you categorically don't want to deal with her?
Sorry you have to deal with this so close to your due date when you have enough going on. Sorry this probably doesn't help much, just wanted you to know there are others unhappy with their health carers.
Good luck.