I was told that HCG is usually expected to go back to zero within about a couple of weeks (even if there is a bit of retained product). Mine was a lot slower (a bit more like Audax's experience) but I had something unusual going on. So unless you too have a bit of an unusual thing too, hopefully you will be under 5 within the week. If your HCG stalls then it would be good to have a conversation with your dr about why that might be.