My a few months old phone wasn't great in the beginning: I was charging every other day maybe. I decided to let the phone completely die to go thru a full discharge. After performing that the phone has got much, much worse. For example, I fully charged the battery yesterday at work, made a few calls on my way home. Checked battery level, it was 85%. Next morning I have 25% and battery usage shows Android OS 96% and Call standby 2%. What is happening?