Default [Q] Out of space

Hi everyone! So, I've been having a bit of an issue with my Galaxy S3 lately (and by lately, I mean it's been bothering me for the past few months, but until today I've been able to use my phone )

My phone is giving me an out of space message, and no matter what I do, I can't seem to fix it. When it first started coming up, it was a bit annoying, but today, my phone seems to have run out of so much space, it can't receive messages, take screenshots (even though it should be stored onto my SD card), or even use the Facebook app without it erroring.

I can't upload a screenshot to here (since my phone won't even let me take the screenshot ), but when I go to the storage settings, my phone says I don't have enough internal memory. It says I have 11.25GB total, and I'm using 1.85GB for applications, 5.27MB for pictures and videos, 34.30MB for audio, 14.14MB for downloads and 236MB for misc files. Somehow that means my 11.25GB space is all used up, so I might have to go back to school for maths, because something doesn't add up . It also says I have 4.30GB free space on my SD card, but that's not causing the problem (I hope)

I've searched for other problems like this, and all of them are for rooted phones, which doesn't help me because my S3 isn't rooted. Also, all of the problems I saw were when people tried installing an app and got the "out of space" error on Google Play store, and they had to delete the app's .odex file, which unfortunately doesn't help me

I appreciate any help anyone has ! Really hoping to be able to use my phone again