I've had the Nexus 6P for about 4 days, and have been able to use it normally for that entire duration. Yesterday, I got a case, and it was still working fine. Today, I turned it off for about an hour in school - and when I turned it back on, it was stuck at the color animations we see after the initial "Google" loading screen. I've already tried powering it off and on, etc. - any suggestions?