My tablet's internal storage suddenly disappeared?!

Earlier today, I connected my tablet to my PC and everything functioned perfectly. However, when I tried connecting it again just now, the internal storage was showing nothing but gibberish characters instead of the pipa label, and all my data has vanished. I had quite a collection of music, photos, and especially files in my Google Docs—a massive pile of various books and entries in Evernote. I managed to back up some of it previously, but certainly not these most recent items. While the programs remain intact, they are completely empty. What could have caused this, and is there any way to recover my data? I haven't saved anything since the glitch occurred. My External SD is also acting strangely.
Please help.