21 weeks and Doctor Visit

I am 21 weeks now. It won't be too long before Samantha Grace arrives! I went to the doctor yesterday for a check-up. My mom came with me because Brian and I leave for Las Vegas on Thursday so he didn't want to have to take Monday afternoon off as well. The baby's heartbeat was 152 and I was measuring just right. Next visit I have to get more blood work to test for diabetes and anemia. She told me I could lay down for it considering I fainted the 1st time :-) I asked her if I would be sent for another ultrasound because I was disappointed that no one told me I could video it and she said probably not because everything looked great and insurance may not pay for another one. She recommended a 3D or 4D ultrasound. She named a place to go but I wanted to see if anyone else has done this and can recommend a place or recommend whether or not it is worth it to get one.