My daughter who has been a superb sleeper since 7 weeks (8.30pm - 6.30am), is now 15+ months and over the past 3 days, she started waking up crying every 3 hours. We mostly left her to cry for a little bit, and she would go back to sleep but on all 3 nights, at about 3+pm she would cry a lot harder and we would have to pacify her before she would go back to sleep.

Last night at 3.30am, she seemed hungry, reached for her bottle of milk and finished all of it (6oz), and took us an hour to put her to sleep (and only if she slept with us, she didn't want to be left alone in her crib). She also had fever last Friday which subsided over the course of Saturday.

Any guess what is going on? :) Thanks in advance!