Small bumps?!

Hi everyone, does anyone ever look at their bump and think "where are you hiding???"....
I'm 5ft 3 and have only put on about 3/4lbs since becoming pregnant (I'm 8stone 4lbs). I'm 23 weeks and due 17th October. 
I met another girl who is due 10 days before me (also with her first) and was so much bigger than me! People constantly say "wow are you even pregnant?"...I work in retail and would have expected a few customers to comment on my bump/being pregnant but not 1 stranger has mentioned a thing to me - im that small! 
Some days my bump is bigger than others then sometimes she is hiding so much I don't even look pregnant! 
I WANT A PROPER BUMP!! 
Does anyone else feel too small for how far along they are??
Xxxxx