Other things do not compare. My son nursed every 2 or 3 hours. He nursed 4 or 5 minutes pre breast. He would nurse for about 10 minutes total. Your milk might be flowing faster than some women.
Babies grow at different rates.
However, your baby is gaining weight so is probably fine. I would not suggest a supplement unless you need to, because God designed mom's molk to be what the baby needs. Other things do not compare.