My daughter is actually tiny due to having hypotonic muscles. So it's now become a way of life for us - but I'm short and I have some really short people in my family anyway... I thought I wouldn't let it get to me but at one stage it did and all I said is "yes - she is small, like a little princess or porcelain doll - not a big fat ogre or a pig!"
I then had a son, who had plenty baby fat rolls but has now grown into his skin and isn't huge now either at the age of 9 - so genetically speaking we've had fun...
Don't stress as long as your child is happy and healthy that's all that counts!!!!!