So I was using my phone (Galaxy s2 running jellybean on tmobile) earlier, web browsing, and I hear a loud beeping noise for about 5 seconds. My phone then shuts off, and after a very long wait at one of the splash screens, turns back on again. It seems to be restored to factory settings. None of my apps show up in the "installed applications" window, although i'm pretty sure theyre still there because it says the same amount of storage is occupied as before. None of my files or music show up in the download app, but they're there if I manually browse the files and look for them. I tried restarting the phone again, taking out the sd card and nothing changes. I can still get texts and call and it is fully functional, I just can't access any of my apps or previous settings or data. I would really appreciate it if anyone has an idea what happened or how to fix it.