Same thing going on here. My little one is 10weeks and she usually sleeps from 11pm-7am (tightly swaddled with a velcro swaddle blanket).
Just recently around 5am she starts to wiggle, squirm, grunt and I get the idea that she is just uncomfortable. She sleeps in our Arms Reach Co sleeper next to my side of the bed so I constantly watch her during an "episode" of the wiggles to try and figure out what is going on. She almost never breaks out of her swaddle (you have to swaddle with her arms straight down to her sides...if not she WILL break out) and it looks like she tries to at 5am. She kicks and wiggles and grunts and then tries to go back to sleep and then starts again.
What I do now is gently un-velcro her swaddle and almost immediately her arms shoot up over her head and she does a huge stretch and about 7 out of 10 times she poops!! lol Other times she just passes some major gas (without crying) and then she kinda settles down.
I usually get up to do a quick diaper change and I nurse her with little stimulation and and do a quick burp and she falls back asleep ( I re-swaddle her).
Then, around 730am she starts up again. I change her diaper (usually she is just wet) and I put her in bed with me to nurse and we both fall asleep again for a good hour or so... (I love to sleep in!! lol)
I hope this passes too because she use to sleep straight through, but I guess can't complain because we usually get at least 5-6hours of good sleep every night with her little wiggly episodes.
Funny how so many of us are going through it at this age...
I only swaddle at night and I sometimes leave her feet out if it's a warm night.