Normally levels do double- so that's probably what they are looking for, BUT I have heard of so many stories of the levels slowly rising or even staying the same and the baby was fine! I know exactly how it is to get those test results and still not be sure of what is going on- it's so hard!
Do prepare yourself that the ultrasound might not show much still, when you are not far along, it's very difficult to tell much from an ultrasound- so whatever you see there, hang in there and let us know how you are doing as you go along. Know that you aren't alone and we are hoping for a healthy pregnancy for you!
Ahh, honey. I know you are so worried. They ARE still rising. I think the statistic is that 15 to 20% of pregnancies have abnormal HCG levels. Try to stay positive. I'll say a prayer for you and we'll hope for the best. It's not over and as there are fluctuations with HCG levels, not every woman follows the exact typical pattern and they go on to have healthy pregnancies. Come back after your ultrasound and tell us what you find out! hugs