weight is no guide on when baby will arrive, wish it was cos my daughter was estimated 6lbs at 34 weeks and was born at 40+4.
it is sadi that babies put on about 0.5lb a week in last few weeks .
If this is your first then all you can do is wait it out, yes its boring, but baby wont come until ready to do so. Just get on with things until baby arrives and try and ensure that baby is in the correct position to ensure that once labour starts the babys head is in correct place on cervix.
apparently only 10% of babies arrive on their due dates.