Nicole - I am sorry you have suffered m/c before amd lost your babies.I can understand you will worry but they seem good to me.We lose the carefree innocence after a pregnancy loss.
It is normal for doubling to slow down

For HCG levels <1200 mIU/ml, the expected doubling time is 48-72 hours.
* For HCG levels 1200 to 6000 mIU/ml, the expected doubling time is 72-96 hours.
* For HCG levels >6000 mIU/ml, the expected doubling time is >96 hours.

HCG levels peak at about eight to 10 weeks of pregnancy and then decline, remaining at lower levels for the rest of the pregnancy. Here is a sample listing of expected HCG levels based on time after conception:

* 0-1 week: 0-50 mIU/ml
* 1-2 weeks: 40-300 mIU/ml
* 3-4 weeks: 500-6,000 mIU/ml
* 1-2 months: 5,000-200,000 mIU/ml
* 2-3 months: 10,000-100,000 mIU/ml
* 2nd trimester: 3,000-50,000 mIU/ml
* 3rd trimester: 1,000-50,000 mIU/ml
Goodluck - how far along are you ... you need to get a ticker .
with hope Trish