hey hun i had a growth scan at 35/5 and was told my baby was small for dates, she was born 2 days later at 36 weeks weighing 3550 (7pd 8) and 50 cms, so she was definetly not behind for dates! if anything she was ahead of dates. try not to stress too much, if theyre happy for u to wait another 6 days b4 having the scan done then they cant be too concerned, plus u'll be almost ready to pop by then too!
best of luck
xxx