3 month old moaning in sleep

[Poppety]

Hi everyone
My 13 week old has recently started moaning in her sleep from around 5.30am and writhing around in her bed and it's driving me bonkers! She is so noisy! She is asleep and doesn't seem to need anything but I have to lie there listening to it until I get up with my 3 year old at 6.30am!
At first I was getting her up and feeding her but she wasn't hungry so I stopped!
She is a very light sleeper and even the rustle of my duvet will disturb her, we don't have another room to put her sadly so she is stuck with us until she goes in with her sister!
Does anyone else's baby do this and what the heck is it!!!
She feeds to sleep around 7pm and wakes twice for feeds and then gets up between 9-10am!

Sounds like my 13 week old however he wakes up with it a bit more. But as of a couple if weeks ago he is writhing around. Moaning, drawing his legs up, and wakes himself up with this every 45-60 mins, till he does loads of farts and a big poo! Usually some around 7-7.30, and the rest between 8.30-9.30am... Really tough as I'm so exhausted and so is he! Another baby in my antenatal group is doing the same and he's the same age. Hope he grows out of it soon. Sorry no advice but nice to know others do it too!!