I'm A 29 Yr Mother Of Two Healthy Children And

I'm a 29 yr mother of two healthy children and pregnant for the 3rd time. My LMP was Sept 13th and I have only had sex twice in yhe last three months....September 3-4 weeks before having a positive pregnancy test and then a day or two after getting the positive test....I have a retroverted uterus....at an ultrasound at 9 weeks I was showing signs of being only 5 weeks pregnant with a gestational sac and yolk sac. At a follow up ultrasound 1 week later the ultrasound tech thought maybe it was a molar pregnancy. There was now a fetal pole and one small ball like shape but not any visible growth of the gestational sac. My HCG levels went from roughly 69000 to 65500 in 48 hours. A third ultrasound a week after that showed the gestational sac, yolk sac and what looked to me like two balls inside the gestational sac. My HCG levels are still going down. I keep getting told it is a miscarriage but have had no signs other then the ultrasounds saying it is a miscarriage so I am reluctant to agree to any furher action at this point. There has been no heartbeat yet, although the third ultrasound did come a lot closer to almost finding one but it was likely just my heartbeat according to the tech. I need a second opinion as if I am now only 8 weeks and viable it would mean I miscarried the first and got pregnant immediately or I have two pregnancies going on at once...both very rare ...or it is in fact a miscarriage? Also could high progesterone levels be masking the miscarriage? We have not tested but since HCG levels are decreasing slowly already what is stopping the contractions from happining??
Thanks