3 month old nap changes

My baby is suddenly sleeping differently.

Shes usually wakes a few times in the night for a feed but will go straight back to sleep, like she knows its night time.

Now shes hit 12 weeks, she’ll wake up at 1am quickly for a feed, then shes waking up at 3am absolutely wide awake every morning and wont go back to sleep for a few hours.

She used to nap for a couple hours at a time during the day, but now suddenly shes only sleeping for 45 minutes at a time.

Shes being pretty grumpy as well 😅 is this normal? Is her sleep patterns just changing?