iPhone Battery

I have the IPhone 11 and for the past month from now, my phone battery has been weird. The battery reads 100% at 9:00 and barely an hour to 10:00 it then reads 1% and it’s now 11:00 on April 2 and it still says 1%. I’ve tried shutting the power off and then resetting my phone but it does nothing to help my problem and I’m starting to think that I should get another phone. Can anyone help me?