Anyone know why?

Delaney • Mom of a sweet little boy 👶🏼 baby #2 on the way 💙👨‍👩‍👦 🤰🏼

So my 3 week old will have a day where he is good all day, eat, sleep and only cry when hungry. The next day he will eat like only 20 ml when we try to feed him he will only sleep for 10 mins and scream all day till 10 pm at night. We do gripe water gas drops swaddle rock and more and nothing helps. It’s like this every other day. ( good one day bad the next) anyone know why? He is formula fed and we poop once to twice a day and pee a lot.