They just like to trick us by sleeping through the night to make us

and then not wanna sleep the next night!?
Think she's still quite young so might take a bit of time to get her in to routine, have you thought about the number 2 milk (hungrier babies) if she's feeding every 3 hours? That might satisfy her more making her feed every 4 hours and also build her up for night time?
Noah got in to a little routine at about 3 months and started sleeping 7 hours without a feed but then all of a sudden he was a wake every 4 hours again for a while! Apparently they can have growth spurts all of a sudden?
He's in a good routine now!
Are you doing things ie bath time, bed time at the same time everynight?
xx