Being called "fat"

Since when is it ok to call a pregnant lady fat? 
I'm 20 weeks and have only put on 6lbs (I lost about 10 in the beginning) so am now just about coming up to my original weight but with a now growing tummy, that's just about to pop out into a bump. 
I've been laughed at whenever I eat (as long as it stays down in going to eat it as far as I'm concerned) and called tubby and I don't think it's been at all noticeable that I'm pregnant until now, so I'm pretty peeved that I've been called fat and chubby (even if it is jokingly)
Before on right, now on left.