Today, my watch (series 7, only 12 months old) battery just died. I normally get a full day without needing a charge. It depleted very quickly, so I gave it a charge for an hour but it dropped again very quickly and went right down to zero. I put it on charge again and left it for a while. I’ve come back to it now not turning on, it is now only flashing the Apple logo and when I took it off charge it was very warm. Can I assume it is knackered?