Sleep Training is The Worst

The first week was AMAZING. Day 3 he fell asleep after 3 minutes. Day 5 he didn't even cry. Day 7 he slept for a solid 10 hours. And then something flipped. He will not go to bed. He cries and cries and cries and my poor heart breaks every time 😭 he wakes up several times and will scream at the top of his lungs. I always wait 10 minutes, go in and tell him his 'goodnight cues' (mommy and daddy love you, and we will see you first thing in the morning. Sweet dreams) I try to be in and out in less than 30 seconds. But hes been crying for 30+ minutes and I caved and brought him out and rocked him until he could sleep again.

I thought he might not be eating enough but he eats at least 4oz of solid food and then nurses 30minutea before bed. We do the same routine every night. I put him in his crib for naps and he does fine. Input him in his crib for 'quiet time' as well and he is perfectly content even when I leave the room.

Is there anything else I can try??

EDIT: Thank you all so much! 😭 I'm a ftm and I always feel like I'm doing everything wrong 😭😭 Hopefully he will start feeling better about bedtime soon!! I will definitely stay consistent and I watch his monitor and sit roght across the hall the entire time he's crying so that I know instantly when he really needs me and isn't just mad that he's in bed