I replaced my Mac screen and now it shuts off when it gets unplugged

I just replaced the screen of my MacBook Air and followed all of the instructions and my only problem was that the wifi antenna didn’t snap into place like it was supposed to, I think I broke it from trying to connect it too forcefully so I just kind of lightly placed the cables and hoped they stayed. But anyways my Wifi works and the screen works and everything is fine except now my computer is a little slower than it was before and my laptop shuts off completely the second it gets unplugged. I know that’s a somewhat common issue but it’s never happened before and happened immediately once I replaced the screen so I think it’s something I did wrong. I checked the battery but it looks fine so I’m not sure. Does anyone have any ideas of what I did wrong?