Do you think she could be overtired? My DS is about the same age and can't stay up for longer than 1 1/2hrs. He doesn't often sleep for more than 2hrs at a time during the day and it's usually only 90mins, but still will go to bed every 1-1 1/2hrs like clockwork. He will also not be settled by anything but booby at night, up to 4 times a night and is fed to sleep too. I don't mind that's fine for me, and I think it's still pretty normal. Thier tummies are still only tiny and during the day they feed every 3-4hrs so why would they not do similar at night?