First off, there is no need to loose important work. Get a fresh uSD card and flash it with Raspbian and with power safely turned off, remove the old uSD and replace it with the freshly flashed one. Windows will not see your linux files on the old uSD card so either get a uSD-USB adapter or download and burn a Linux live distribution to run on your PC. It will be able to find your important files in the /root partition. An adapter will allow you to do this on the RPi itself. You can then transfer the files back to your new uSD card.
Second, BACK UP YOUR FILES to a safe place...your PC hard drive or another uSD card using "SD Card Copier" on the Raspbian Accessories ,menu. Do it as often as you create or change them. Best bet is to learn to use "rsync" or another backup program that will do it automatically rather than depend on your memory. The ability to swap out uSD cards is an important feature of the RPi so you can isolate your messing about from the more critical work you do on it. I don't own a "smart" phone so I can't help you with that.