DD is 12 weeks old. We have got her into quite a good night time routine - she is generally down for the night from 8pm to 7/8 am (though her bedtime tends to vary an hour or so either way depending on how the day has gone). She usually sleeps for a first stretch of 4 hours and then wakes hungry every 3 hours.
For the last couple of weeks her daytime naps have turned into total chaos however! She used to have maybe 2 longer naps and 2 shorter ones. Now she repeatedly wakes up after 25-45 min (usually after 30 min). I spend 20 min trying to get her back to sleep which sometimes works but usually doesn't. If she gets past the magic 45 min mark she can then sleep for 2-3 hours.
I've read that waking up like this can mean she's either over or undertired. She tends to be obviously tired after 1h20 min of awake time so I doubt she is undertired. I have tried windng her down after 1hr of awake time so she is asleep at the 1h30 mark but this doesn't help her sleep through either.
Any advice? I feel like I spend the best part of the day either BFing or trying to get her to nap. On a bad day she has 5x30 min naps and then goes into a total overtired meltdown at bedtime. I'm trying to follow an EASY routine with her but this goes to pot when she's awake after 30min. I'm starting to wonder if it's a developmental phase and I just need to wait for her to grow out of it?