Thanks Dachlostar. Yep, I do breastfeed and thought that she was nursing frequently to up my supply, but yet during the day - she's a 4-hour feeder and doesn't seem to be wanting to be fed more often, or for longer per session.

I do a mixture of sleeping styles with her - the first shift of the night, I sleep with my husband (separate room). Then after that, I sleep in her room in a separate bed - and after the 4am feed, she sleeps in bed with me so I can feed her while I'm nice and relaxed.

Hopefully she'll settle down, and this is what I thought would probably happen after this fussy period - but then I got confused by everyone telling me that now she's used to freqent night-time feeding, she'll never go back to what she was doing before.