From babymed.com---
"The HCG level usually rises as pregnancy progresses, doubling every 48-72 hours until 11-12 weeks of the pregnancy. HCG or Human Chorionic Gonadotropin is the pregnancy hormone which is produced by the placenta and is detected with pregnancy tests."
So hcg doesn't have to necessarily double every 48 hrs then right? It could take it technically 3 days to double! I hate to keep quoting websites and all, but I'm just reaaaaally trying to still hold out some hope. I know you're gearing yourself up for the worst news, which I really don't blame you. Someone who has been through as much as you have, I can only imagine how heartbreaking it is to be disappointed over and over. But, at the same time, I can't help but to try to grasp straws for you because I have been stalking this story for so long! I've kinda been living vicariously through you and this thread. I think that's why I'm trying to stay so optimistic. Maybe tomorrow will be the unexpected good news that we all are wanting you to hear.