last night i downloaded the newest update for lollipop onto my Nexus 5. since then my phone has pretty much had a mind of its own! it shuts down when ever it feels like it. Then once off it wont turn back on with out screwing around with it. when it does turn on it has to optimize the apps. if i turn the screen off it shuts the phone down. i factory reset the phone in the settings and it didnt help. the phone worked A+ since i bought it in June. first time its ever screwed up like this.