iPhone 6 shuts down

Hi,

I use an iPhone 6 with OS 11.2 currently. My phone has been shutting down continuously from yesterday onwards. Every time I have to connect to the charger and then phone starts on itself. Sometimes battery is all drained out and the other times it’s not.

I’ve tried to solve the issue by turning off notifications of all apps and also changing my phone date to December 1 since I saw some support forums asked to do that.

But nothing has worked and it’s very difficult.

Please help.. :(