My son is 12 weeks old and screams when I try to nurse him. We have a few feedings where he doesn't scream but he will latch and let go the whole time and be done after like 7 minutes. I am already supplementing each feeding with 2-3oz of pumped milk and one feeding with 4oz of formula. As soon as I give him the bottle he's fine. He wasn't gaining weight so dr told me to supplement each feeding.