Low Fetal Heartbeat and Confusing Progesterone Levels at 7 Weeks Pregnant

Hi Moms,
I was wondering if any of you had similar problems during any of your pregnancies. I am 7 weeks pregnant with my 2nd child. My first pregnancy was smooth sailing, but this one has had problems from the start. First, I began with brownish spotting at 2 weeks pregnant. Then, I had an episode at 6 weeks where I experienced dark red vaginal bleeding that stopped pretty quickly. At that time, I went to my OB and they checked my hcg and progesterone levels and sent me to the hospital to have a transvaginal ultrasound. The ultrasound showed a fetal pole and a heartbeat of 95, which is slow. My hcg was within the limits that would indicate a 6 week pregnancy and my progesterone was 19, which was adequate. I had my progesterone and hcg redrawn 72 hours later and when I went to the OB for my prenatal visit the following week.Tthey told me that my progesteone had dropped to 13, the hcg was rising but not as it should and they sent me for another transvaginal ultrasound. This time the heartbeat was 50. I was told that the pregnancy was not viable and I would probably miscarry. Well, today the office called me and the progesterone level went up a little which is not what they expected. I'm going back on Tues to be seen and I'm to call them if I have any more bleeding or any cramping (which I've had none). Sorry for all the numbers and info, but has anyone else gone through this up and down with the progesterone and the uncertainty of miscarriage. I had pretty much accepted that I would miscarry especially with the lowering fetal heartbeat, but the rise again in progesterone is confusing. I'd appreciate any input from anyone who's had a similar experience. Thanks! Also, the second office visit in which I was 7weeks pregnant showed that the fetus was still only measuring at what it had a weeks earlier (6 weeks). This waiting is so hard!