Why does my baby thrash in her sleep

[TangBloodyFastic]

12 weeks
Currently co sleeping and goes down fine. Wakes around 1for first feed. A bit restless after
Around 3am she wakes, has another feed and then will go back to sleep but thrashes her legs, arms and constantly moves her head. She then calls for milk regularly until we get up
Have tried winding - makes no difference. This morning I bicycle'd her legs and she 💨 but still brought her legs up and slammed them back down after and wouldn't settle and ended up getting up at 5:30. She seems constipated today so far

She is keeping me awake and I feel she isn't getting a proper nights sleep because of it - her eyes are mostly closed but she does open them periodically so is not getting much deep sleep

Could this still be her reflux? Her symptoms have mostly stopped through the day so have stopped the gaviscon but wondering if still bothering her on a night and if I should give her a sachet before bed? But I'm not convinced the gaviscon will do much when she's having it at 8pm and the issues start around 3am. It wouldn't really do much would it after that time?
I'd rather not wake her up properly to give her another sachet at 3am as I don't think either of us will get back to sleep

Any suggestions?

I read there's something called an 'acid dump' around the early hours of the morning, so it could possibly still be refluxy symptoms. My 11 week old twins are exactly the same so you have my sympathies!

Would you ever swaddle her x

Thanks @MilsCookie hope it's not but will have a look into that

@WeeSunhine2018 I've swaddled in the past but it sends her into a meltdown
She's in a sleeping bag and it's her legs really that are the issue, she brings them up and bangs them back down - repeatedly - for what seems like hours