Usually I will throw out the milk if it’s more than 1 hour :’)
Maybe you can see your milk bottle teat? The flow might be too slow for your baby. Or maybe give lesser milk since your baby consumes lesser than what you’re giving?
Also, I heard from my son's infant care teacher that some babies do like their milk a little more warmer and tends to drink better. so you can try adjusting your baby's milk temp by a couple degrees!
Pearl Lam