iphone 6, temperature warning, then just died, won't come back on

My phone has been perfectly fine, got it in August. Today just sitting at my desk the temperature warning comes on that it's too hot and needs to cool down, phone feels perfectly fine to touch, was not exposed to hot or cold temps, battery drains, tried to charge and won't charge, just get the battery symbol with a thin red line, will not soft or hard restart and is not recognized by the computer.