Will I miscarry?

Hi everyone, this is my first time writing, but I am feeling desperate for some advice. We have been ttc for over a year and I rarely ovulate, so they were about to start me on meds (chlomid). Anyway, then by some miracle I DID ovulate and found out 16 days later I was pregnant. We felt it was honestly a miracle (my husband also has a very low normally shaped sperm count). Anyway, my first two hcg tests were 600 and then 1,812 two days later (this was on day 18 and 20 post-ovulation). Then, less than a week later I had some very light, beige colored spotting. The next day I called the Dr. and they said I should come in that day to have my levels drawn again. SO on Monday (one week after my first draw, my hcg level as up to 12,908.5. They also had me get a rhogam shot b/c my blood type is A negative. Anyway, the next day, Tues., I went in for my first ultrasound and they could NOT see a heartbeat. They predicted I was between 6-7 weeks pregnant and said it's likely I will miscarry now. I did not expect this at all and I am honestly shattered. I really thought this baby was a miracle and a gift from God. I am still having the light, beige colored spotting off and on (only need one light pad a day). My question is if it is still at ALL possible I won't miscarry... I go back in one week for a 2nd ultrasound, unless I miscarry before that. It's so awful to feel like you are just waiting to lose your baby. :(
They also have me going in for new hcg testing every 48 hours. I went today but don't have the results yet. However, the Dr. did say my levels could continue to rise even if I'm losing the pregnancy. Has anyone ever had this happen?
How common is it to not see a heartbeat at 6-7 weeks?

THANK YOU, so much, to anyone has any feedback. I so appreciate it right now. I feel so lost.

God bless,
Emily

[AnnieBrooke]

If the results continue to double, I would not give up hope at all.  You might not have been as far along as you thought you were.