Need some help with baby's sleep!

We were doing SO WELL.

Now baby girl has a new bad habit it seems. Took us so long to sleep through the night. And now she has changed 🙁

Went from sleeping soundly from 8:30 pm to 6:30/6:45 am every single day.

And now she wakes up every day between 3:30/4:00 am and whines for no apparent reason (won't take a bottle and doesn't need a bum change). Then by 7:00 am shes quiet and tired and sleeping again until approximately 11:00 am if I dont wake her up.