Smartphone constantly restarts on its own

[overther]

I have a Sony Xperia Z3 running cm14, that has served me well over the years, but recently it's acting a bit weird.  At first it would restart when I dropped it, I blamed it on the battery getting out of place,  since the back glass is broken and a part of the battery is exposed. Yesterday though, the phone started restarting randomly, even when I have it on a solid surface, just watching a YouTube video, not even touching it.  It works great while charging, while for some reason it will super charge after 50%,  (it takes about an hour and a half to reach 50%,  while it takes less than 10 minutes from there to reach 100%)  this started happening from yesterday as well.  The battery is relatively new,  i have changed it less than a year ago.  

I also tried to calibrate the battery, but it didnt help at all. 

No new apps installed or settings changed. 

[airENOwevEr778]

Either your battery needs replacement or the drop has led to internal damage.