Dehydrated cow

I feel like a dehydrated cow. My baby seems to be permanently latched to my breast. Did I overfeed my baby? The pediatrician always assures me that my milk supply is sufficient. I cant help to compare my baby to his cousin. One week after birth my sister's baby weighs 4 kg, while my baby weighs 2.9 kg only. I once once scolded for benchmarking. Am i willing to swap my baby with my sister?

What is the reason for my low milk let-down? Despite of 20 ml pump output or sometimes even lower at 8th week, Our pediatrician still convince me to breastfeed without cow's milk supplement. My baby is not a cow. She said I have many allergies and I should not switch to cow's milk. She doesnt want to introduce foreign protein to my baby. Shhh... I did one dose in the past secretly. The bstool was too sticky. Shhh.... I should have told her. Anyway, I will test my patience and endurance. Up to when can I sustain breastfeeding?

What is wrong if we introduce foreign protein to my baby. Sooner or later he will be eating ice cream,    Chocolates , and other milk products.