Problems with my iPhone 5 since iOS 8.4 update

Ever since I updated my iPhone 5c to iOS 8.4, I've been having tons of problems. First off, my storage is extremely limited. I've had to erase my phone, restore it twice since this update & I think I'm gonna have to do it again soon. I just wiped my phone last week. It was saying it had zero bytes. When I wiped it & restored it, it said I had about 9 GB available. Now, not even a week later, it says I have 2 GB of storage available. I have not installed anymore apps, in fact the 1st thing that I did when I noticed this problem is delete apps that the previous update had stored with no problem. The biggest apps I have, storage wise, are 100MB. How can I fix this issue without having to wipe & restore my phone every week?

My 2nd question: my music app has been so screwed up since the latest update as well. My phone keeps putting multiple songs that are exactly the same in1 of my playlists. I erased that playlist & am making it all over again. Also when I sync my phone to iTunes, it will not put the songs in alphabetical order as it appears on the screen in iTune. Please help me get out of iPhone ****! Any advice is greatly appreciated.