Advice on how to relieve night time gassyness?

So my EBF 7 week old absolutely will not burp during night time feeds. She falls asleep while eating and just won't burp so as the night goes on she gets more and more uncomfortable because of all the gas built up. By morning she used to be able to fart it out after some pushing and wiggling but that seems to have stopped working & she's starting to get so uncomfortable she's crying. I also think it's affecting her ability to sleep because she'll sleep up to 5 hours and after that first night feed she'll only sleep 3 hours after that.

Anyone have any advice that would help me prevent her getting so gassy at night?