iPhone 5 storage problems

Hi,

So I've been having issues with my 16gb iPhone 5 for a while now, but it's starting to become super unmanageable.

I basically can't install any apps anymore, or download new updates etc. - I have apparently used 13.3gb of storage with 0 remaining.

However, there are a couple of things that strike me as odd.

1. I have 930 songs on my phone, which are apparently taking up 8.5gb of storage. And this doesn't seem to change even if I delete a whole album. Is this normal?

2. I've deleted around 5 of my largest apps, including Facebook, messenger, a dictionary, a translator and a game. But this didn't make any difference to the amount of storage I had - or at least only a minimal difference. I currently only have 6 apps.

3. Similar example - I literally just deleted my only ticket in passbook which was apparently taking up 635mb of storage. After deleting it, my available storage was still 0.

Basically, I can remember in the past having over 1000 songs, and at least 12 or so apps. Has something happened, and is it a problem I can fix?