Android Gallery and Music empty?

I recently discovered that all my photos on my phone has disappeared from the Gallery application. I connected my phone to my computer, and the images are still present in DCIM/100MEDIA/ directory. I did a backup of my photos, tried stopping the phone, the app (gallery), removing the cache from that app but no luck. While searching for a solution online, I found that some people also had the same problem with the music app. I have albums that used to work, so I was sure to find them. But now they also have disappeared. So Gallery and Music is empty despite having files in the correct folder. Regarding Gallery, if I take a new photo, it will correctly be added to the DCIM/100MEDIA/ folder, with the name IMAG001332.jpg (for example), but with 1332 being a correct incremental number (not starting from 0), which is even weirder. I don't know what to do to fix it! Does anyone can help me? (Note: I have an HTC One S) Update: I did a reset of my phone (http://www.htc.com/us/support/htc-one-s-t-mobile/howto/315367.html) without any luck.