You didnt do anything wrong, love. I used to question myself the same. My baby is now at 3 weeks. She still being fussy from past midnight till sunrise. Sleep deprived is so common. Now she has developed a new habit. She will piss off even when she farts! Crying out like i smack her or something. Haha. It can be frustrating when they cry alot. But just remember thats the only way they can communicate with us. Sometimes they just want to be cuddle. Cos they had stayed in our womb for 9 months. We just need to tell ourselves be patient. This shall pass soon. And you’re not alone.
That's like my first born. Sleep alot in day time and wakes up every 3 hrs for milk. That's her pattern until before 1 years old her pattern changed to sleeping long at night. Whereas for my second born is the opposite. What I can share with you is to FM before sleep or long latch then burp, massage, swaddle and baby sleep well. They will have their pattern change every now and then so you will of course have the sleepless night for start.