Memory keeps filling up on its own

Hi there,

I'm having a recurring problem with my iPhone 4S.

It's 8GB, but I only actually have 5.4GB capacity to begin with. For some unknown reason, my memory keeps filling up even though I'm not downloading anything, and I have to keep deleting more and more apps, photos and music.

For example - it'll say my memory is full. So I'll go delete a few photos - available space will still be 0 bytes. I'll delete an app - this will free up about 80MB, or 200MB at the most. I close the settings, go back in, and it's instantly dropped from 200MB to 180MB. Close then go back in again, 180MB to 153MB, and so on.

This is really annoying me now, as I've only got 200 photos, 200 songs, and 10 small apps. I keep having to delete everything, and even when I delete things to free up space, it often still says my phone's memory is full.

Any suggestions would be appreciated.