I'm not too familiar with your history as I'm new to this board, but it seems incredibly unlikely to me that you're the cause of his skinniness.
My AAP book says not to worry about using a pacifier; if baby is hungry, they will NOT want a paci and will scream until you feed them.
Makes sense.
Eating every 3 hours sounds pretty normal, as well.
So it doesn't sound to me like you did anything wrong at all.
I empathize with the formula-feeding thing, I have a very low supply and only produce about 10 oz a day, so DS is primarily formula fed. So sad.
My AAP book says not to worry about using a pacifier; if baby is hungry, they will NOT want a paci and will scream until you feed them.

Eating every 3 hours sounds pretty normal, as well.
So it doesn't sound to me like you did anything wrong at all.
I empathize with the formula-feeding thing, I have a very low supply and only produce about 10 oz a day, so DS is primarily formula fed. So sad.