17 week doctor appointment

This afternoon I had a doctors appointment. I was surprised when they took me back and told me that the doctor was going to do another ultrasound. I had 2 with the tech at 6 and 9 weeks to make sure the baby was ok since there were some miscarriage concerns. But now the doctor has done one at both of my regular appointments. I'm not complaining, I love to see that they baby is ok, and watch him/her wiggling around in there (he/she was waving today!!). The doc said he was doing it because they doppler is sketchy at this point to find the heartbeat so he would rather do a quick ultrasound to check on the baby. He tried to look at the sex but it wasn't a very good ultrasound machine and the baby wasn't cooperating. My weight is good so far, at 12 weeks I had gained a pound, and at this appointment I was down a pound. So I'm happy to be almost half way with no weight gain. Because I am heavy to begin with it is good to keep my weight gain minimal. And we all know how it comes real quick at the end. My placenta is still low, I asked him at what point they consider a low placenta a placenta previa and he said it is already called that, but that my placenta could still move up as the baby grows, they just have to watch it. Kind of scary, I had a very uncomplicated pregnancy with Dylan, so it's odd to me to have anything wrong. Sorry for the lack of pictures lately, I haven't been able to find my camera cord since we moved, but when I do I will post some new pictures of the house, updated pictures of dylan, and more accurate belly pictures.