Measuring big?

Charlene

So my midwife informed me that I'm measuring over 29 weeks, more than 3 1/2 weeks further on than I am. I've a growth scan booked for my 28week check up. My first son was 10lb 10 but they had never picked up he was big so this experience is freaking me out a bit! Has anyone else experienced this? What do they do if baby is going to be big?