Baby’s sleep pattern

So my baby is 1 month 2 weeks old & he was usually sleeping great at night time he did his 2 hours and a half & then woke up to eat but would fall asleep right away..about a week ago he started just sleeping one hour so he’s waking up every hour at night & stays awake for a good while...I’m curious to why his sleeping pattern change so much & so fast I thought the bigger they get the more they sleep through the night. Any one have this experience? What’s your baby’s sleeping pattern? Tips?