My samsung S6 Battery is depleting RAPIDLY

A

AC Question

That's basically the question ..

it just happened suddenly .. i've been using this phone for almost a year and just last week ,for some reason , the battery started getting depleted rapidly . like , the battery is 10x less efficient than it used to be .

-For example , my battery was on 70% charge when i started sleeping . I knew it was depleting fast so i put on the Ultra Power Saving mode . 9 hours later , The battery was LITERALLY 0%.

I'm just gonna provide you with things i did relevant to this problem:
-I have rooted my phone around a month ago ( the moment i rooted the phone , there were no problems at all)
-I have downloaded several APKs from the internet
- I rarely use my phone , so i dont charge it overnight ( in other words , my phone's battery condition should be pretty good )
-I did system reset several times but nothing has changed

Thank you so much :)