Why is my ultrasound quality so awful?

This is my 20 week ultrasound picture of my girl and this is all I got and didn't even get a gender shot. Doctor took no measurements or anything. The screen looked like this the whole time. My other two ultrasounds I have look like this, too. It's so upsetting. Plus, my doctor's staff is so rude. 
Edit: Not overweight at all. Pre-pregnancy I was only 120 and I've only gained 10 pounds. So definitely not that. I guess the machine is ancient. Sucks because we haven't gotten a good picture at all throughout the whole pregnancy. It was supposed to be our scan, and I went in and he said it was just for fun and we left in 2 minutes or less. And yes, this is a permanent ultrasound machine, not a portable one. 
Okay, yes! I'm definitely switching! I like my doctor, he's nice. But his staff is so rude and awful and I hate having no good pictures of our baby girl! It's my first pregnancy and this is so disappointing.