Feeling really guilty

To

I’m not sure why I’m letting this get to me, but me and my friend have babies 1 month apart. Mine is 8 months hers is 9 months. Well her baby is significantly bigger than mine. Her son is 20+ pounds at and mine is just making 18 pounds. She constantly makes comments about how small my son is. Saying stuff like “you clearly don’t feed him enough” “he only eats 3 containers of baby food a day? Mine eats 3 containers every meal” and now I’m feeling guilty because I know my son is small, and what if it really is because I’m not feeding him enough? Or what if it’s something I’m doing why he’s not gaining. He has had a lot of problems with his weight ever since he was born, but lately his pediatrician says he’s right on track just a little smaller than most his age. :(