why haven't I had another ultrasound?

So I had my first ultrasound at 10 weeks which I thought was normal, ok whatever. Then I had another at 14 weeks where the women insisted she couldn't tell me the gender and I would have to wait until she was born, I'm 31 weeks now and they refuse to do another ultrasound, like do they just not want to check on my baby? I thought I was supposed to have more ultrasounds then this. I feel like they don't care for me and the baby enough. My doctor and nurses are also very very rude to me.. advice ladies?