So confused

So this report from my health link says my baby's heart rate was under 57 bpm. I was 8 weeks at this ultrasound. Everything I've read says that there would be 0 chance of survival that far along with this low of a heart rate. I'm now almost 10 weeks with no bleeding or pain. I had an appointment today and they were very positive about everything and just scheduled me for another ultrasound Sunday just to make sure. Wouldnt my doctors have prepared me for the worst? They didnt even call to tell me the heart rate was that low. They called me the day after to inform me that my due date changed and that was it. The doctor did say the heart rate was a tad slow but by now it should be up to at least 120. That's not a tad...