Big baby??? what do you think?

My baby weighs 2lb at 23+6.. My bump also shows I am measuring big too, and every time I have a scan it dates me at 1 week and 1 day ahead!!

I have scans monthly due to being classed as "high risk" through previous medical problems. 

DOES anyone understand why my bump is measuring bi? why the scans always put me 1 week and 1 day in front? Why my baby weighs 2lb already I was told off the sonographer my baby is 82nd% rather than 50% I have no idea what he means by this? But he did say my baby is bigger than average. 

Any help would be greatly appreciated/ xx