How can I combat 3/4am wakefulness?

[Champagneformyrealfriends]

My 7 week old dd has so far been a great sleeper. We put her in the cosleeper at 7:30 and until a couple of nights ago she's slept through apart from feeds. The last few nights she's been waking at 3/4 for a feed but refusing to go back to sleep, just crying unless she's held. This morning I've brought her downstairs and put her in her bouncer and she fell asleep nearly straight away .
Our room is warm enough (18-20 degrees) and the co sleeper is next to me so she can hear me. I just can't think what could be waking her up! Any advice would be greatly appreciated.

Maybe she prefers the bouncer?

It's only been a few nights and one event of her sleeping on the bouncer, so it's hard to say what.
Could be the dad breathing, lack of noise, different light, that the bouncing did help. Who knows?

She does love the bouncer I've a feeling we'll be taking that thing everywhere we go.

Ds does this around 4:30/5 am and he is 8 weeks, discovered it's wind. He gets really fussy and grunty until he does about 3 massive pumps or I wander around with him and he burps. Sometimes takes half an hour but as soon as is done he's straight back to sleep until 7am. However -he doesn't go down to sleep until 9/9:30pm, sleeps until 2/2:30 wakes for feed then wakes again for feed at 5 ish and that's when the grunting starts.

Thank you I'll try that!