iPhone 6 iOS 11.0.3 Runs out of battery quickly, not restarting

Hi,

I've recently updated to iOS 11.0.3 and the battery has been draining super fast since then, it hasn't even been a year since I got the phone. I've been using it in low power mode as suggested in the forum and it seemed to help the issue a little bit. But today it ran out of battery and isn't starting up even after plugging it in for charging. It just shows the red battery with the plugged in symbol and isn't starting no matter how long I wait. Any suggestions?