I use photoshop and every time I save something and try to bring it back later, it comes up as "Index"
Am I not saving it correctly or is there something I have to do to turn it back into layers?

what image type are you saving it as? if you want to go back and make it into layers/fix it another time, save it as a PSD/PPD file.

if ur saving a pdf then nothing pops up.
if u save as another type, just click ok or w/e to everything..
i usually save as gif soo im not sure..all my pics or animated or have transparency.

... If your base layer is named index, you've succeded in saving your image as a .gif file type. It would be called "Background" if you'd saved it as a .jpeg file.

(As previously stated, save as a .psd file to retain layer editing capabilities. If you're saving a image to use on the internet, always use the "Save for Web" function. It helps a lot when you get into different filetypes and everything.)

If you just want the picture to turn up normally, not a PSD, when it says index do:
Image > Mode > RGB color