I waited to install 9.1 "upgrade" so any bugs could be worked out. OOPS - didn't wait long wnough. I am sitting here watching the battery drain on my iPhone 6. Used to get a few days' battery life. Now getting only a few hours - with Nothing turned on. Unplugged phone from charger an hour ago - went from 100% to 75 % battery already. What can I do to reverse this???