huni,
i dont think your a bad person (i smoke myself). i myself have got no children but my sister who smoked all through her pregnancy's does (15-20) a day, she tried her best to quit but like you couldnt and she gave birth to 2 healthy children my nephew was born 6lb 5oz and my neice was born and my neice was 5lb 14oz (she was 3 days early and by c-sect and had a lot of fluid round her (she is now a chubby happy 1 yr old). sorry to babble what i was meaning to say is she smoked through both and where both healthy weights.
try and not worry huni
sorry that i cant answer about the scan but im sure some the wonderful ladies here will be able to help.
take care and enjoy your bubba.
rach xxxxxx
you are going to a fantastic mummy