Only purchased music showing in iPhone 5s/ cannot add music from iTunes

Hello all,

I have an iPhone 5s, running iOS 8.1.3, and the iTunes on my laptop is also up to date with the latest version. Last night I was dragging and dropping music from my iTunes library to my iPhone as normal - but then I suddenly noticed that all the music in my iPhone Music library had disappeared, except for things I'd purchased. I didn't change any settings or press anything by mistake or do anything different whatsoever, it just suddenly happened. Now whenever I try to drag and drop or even sync music from my iTunes library to my iPhone, nothing happens - the music does not appear on my phone. I have "Show all music" checked on my phone, but still only the purchased stuff is showing up. I don't use iTunes match or iCloud or anything like that either, I always just drag and drop music from my laptop onto my phone and it has always worked fine up until this point. Can anybody help with this? Thanks!