7 weeks ultrasound no fetus

So I went in for my first ultrasound last week and was 6 weeks along. Had a perfect sac but with no fetus. My HCG and progesterone levels were nice and high, too. I went back in two days ago at 7 weeks and again a sac measuring perfectly but still no fetus. They took blood and, again, my HCG and progesterone levels were great. I have had no bleeding or pain. The doc gave me a 5% chance of having a viable pregnancy but is sending me to a specialist to see on Monday. Has anyone else gone through this?? I've already had a miscarriage and now it looks like I'm going to have another...