I'm embarassed

I feel like this makes me a horrible mother. My 2yo is perfectly healthy he's just over 30 pounds. He's a great eater and is very healthy. My 9mo is a great eater as well he eats so much I'm surprised he's not incredibly fat. But he's small he's so tiny 13.5 pounds. It makes me feel like crap. Everyone elses 9mo's are huge. They have rolls and are chunky. Not my son. He's tiny. He's always been tiny though. Was 5.5lbs at birth. But Z his brother was an ounce shy of 6lbs at birth. They were both tiny, yet Z is normal and Ry is so tiny. The only difference between them is Z was formula fed from age 4mo because I was booby trapped. My milk supply was low because I wasn't drinking enough water, was stressed from all the moving about and he didn't have a good latch. Every doctor I've talked to has just pushed formula our way for Ry. I don't trust doctors or nurses or really anyone for that matter. I was pushed to do stuff I didn't want to do. I was told things that weren't true to scare me into submission. Now I trust no one. I barely trust myself. I'm always second guessing what I do. So I'm afraid for my son. I'm afraid that what I'm doing is not enough. I nurse him on demand and through the entire night. He eats babyfood well. I feed him as much as he will eat. He likes yogurt, bananas and avocado. We use some jarred food because I just cannot make every single thing he eats. Does anyone else have a small baby what did you do to avoid people judging you or to avoid it stinging so bad when they do. I'm sick of the comments on how small my son is and the suggestions of formula. I'm just upset. I'm really upset. Thanks for listening.