Possibly dumb question.

Rachel • I have 2 amazingly beautiful boys! One turned 3 in December, and his little brother was born October 7th! 💙💙
When you ladies say your milk supply is low how do you know? Does your baby seem more hungry....are you but pumping "enough?"....is your baby not gaining weight? I obsess about my supply being low but my 13 week old seems content and is gaining weight.