HCG not doubling! Possible miscarry? Help!!

Try not to worry! But look at this chart! Once your levels get to the 1200-6000 range it can take 72-96 hours to double. 

I think after the hcg reached 2000 it can take up to 4 days to double. It rises slower. It did rise, so that's a good sign. It's also a good sign you had a heartbeat. I would wait and see what your next ultra sound shows. Try not to stress, although I know that's hard. 

Yes I have a very close friend who had a similar experience 3 times in a row, she never bleeds HCG lvls just go down and heart beat stops. Best advice although I understand how hard it may be is to hunk positive and not get wrapped up in what could be or go wrong. Any little stress is unneeded stress for baby and does impact a lot. Best of luck I will pray your baby shows you some more HCG :)