Nexus 6 Restarting and Battery Issues

Hi Guys, I really would like to ask some help with my Nexus 6 in which the battery drains to fast and some message always appearing once I try tuning it on back again.

It all started just last week when i noticed that my battery drains to fast, in which lets say the battery has still 70% of power then when Im about to using, the fone will immediately turn off saying the battery is already 0%. But once I try to charge it, it'll be showing that the battery has still 70% of power. Aside from that, every time Im about to turn it on after the knowing that my phone has still enough battery or once I tried to plug the adaptor. A message will appear stating that "Apps updating 15 of 135" something...

I've tried to reset my phone hoping that something that I've downloaded probably have cause my phone to malfunction, but still no use. The battery is draining too fast and that updating of apps is still showing and it'll take atleast 4X I need to turn on my phone with the charger plugin in order for the phone to turn on properly.

Would anyone might know whats the problem or whats causing my phone to malfunction in that way?