My 1st hcg result at 5 weeks was 256, the 48hrs later, 520, the another 2 days 1590, then I had an ultrasound that show the sac and tiny little embryo inside the uterus. They lost the other 48hrs blood result, so after 4 days my level is 5790. It didn't dbl. And everyones says it should dbl every 48hrs... Should I be concern that the embryo might be having problems???