not sure if it's normal but my DS is the same - he had a horrible sleep last night but has been asleep for just over 2.5 hours now. i snuck a 'dreamfeed' in when he started to wake at 45 mins to try & extend his nap but this is a record. normally he's a 45 min catnapper, maybe 1.5 hours with some help.

as long as she's getting lots of feeds, then it sounds like she's fine - just catching up on some rest!