iPhone music randomly disappearing very angry!!! iOS 9.2

Hello Apple community. I tried to search online for an answer but couldn't find a suitable helpful response. I would like your help for a problem that is very puzzling and very frustrating.

recently I just downloaded iOS 9.2 on my iPhone after upgrading from 8. Now, there are some new design stuff that I mostly ignored, but suddenly a problem occurs, where my music on my iPhone (downloaded from iTunes manually from my computer) randomly disappears! This is extremely frustrating! It has happened 3 times in the course of a week, and I had manually re-inserted the music twice (they were fortunately, still intact on my computer). I suspect this is the fault of iOS 9.2, because there is this mysterious music icon at the bottom left of the lock screen while music is playing, and also a very redundant revamp of the Music app, as well as the introduction of a phone icon next to every song but I don't know what it does.

does anybody in the community know what they did to my iPhone? I would really appreciate your help!

edit: I've memorized my entire playlist because it's what I have for the past 2 years, so the deletions are immediately very obvious! Also, alphabets that sort the song titles by alphabetical order sometimes appear and reappear like a magic trick, it seems random, so I know Apple is messing with my music somehow!