Low HCG but rising normally??

My HCG levels are as follows:

14dpo - 20
21dpo - 120
24dpo - 291
28dpo - 1207
35dpo - 8710

They are lower than normal BUT they are doubling well within the range that they should be. My question is - is it possible to have a NORMAL and SUCCESSFUL pregnancy with such low HCG numbers?? I had an ultrasound at 6w1d (1 day after my levels were 1207) and all they saw was a gestational sac measuring 5w4d. They said it could just be too early to see much more and didn't seem too concerned. I have another ultrasound scheduled for next Tuesday when I'll be 8w1d...Do you think I'll finally be able to see a heartbeat?? Or is this pregnancy doomed??

I've had 3 prior miscarriages and have NEVER been lucky enough to see a heartbeat with any of them so i'm really anxious and nervous at this point.

Thanks for any and all replies!!!

[little piggy 2]

im not for sure if this will help you but at 6w1d i found out i was having twins but only one heart was beating so we scheduled another appointment for 7w1d and at that time both hearts were beating but the 2nd baby is still measuring small but fine i go back today for my 9w1d appt. to see how they are progressing. its stressful, i know. with your #'s rising and doubling i feel you have a good chance but im not a doctor. keep us posted anxious to hear if you get a beat.

[Hopin4aMiracle]

Thanks guys.  I really hope so.  It's just so overwhelming when you see all these people with incredibly HUGE numbers and mine are constantly on the low side of normal.  I really hope that I have good news to report at my ultrasound on Tuesday!!!

[Myah's Mom]

When I started posting on this forum, I was overwhelmed with the number of stories of women who had "low-normal" hcg levels and perfect pregnancies. If your Dr isn't concerned, don't let yourself be! You should see much more at this next ultrasound-hope all is well then.

[TrishZ]

Here are my HCG Levels.  Not sure is these are noraml:

Day 14: 93
Day 16: 141
Day 18: 225
Day 26: 3487
Day 30: 7954

I think my numbers are low too.  I can't seem to get any straigt answers from anywhere.