Most likely having a miscarriage

In July I had a miscarage and it was devastating. I got pregnant right away with my rainbow baby just 2 weeks later. I had my first ultrasound at 6w 3d, everything was just fine and there was a heartbeat. Went back today at 9 weeks. And had a transvaginal ultrasound done and my doctor said I was measuring at 8w 2d and he couldn't see a heartbeat. He was the was the one that did the ultrasound on his machine (he said it didn't get great picture like the one at the hospital did). He told me not to be optimistic. Is there even a chance he is wrong or it could be the crappy ultrasound equipment they have?! I'm so scared, what was suppose to be a happy day turned into a nightmare. I have another ultrasound tomorrow at the hospital I'm hoping with everything he saw was wrong