First of all, don't post a message requesting help on a Photoshop problem in a forum associating with Acrobat Reader for iPhone & iPad!
Moving this thread to the Photoshop forum.
Maybe you did not save it in that position. Get into the main menu File/Open Recent and see if it's there. Another option is to make a research among the files in your computer using the date of the saving as a filter.
You need t have good housekeeping.
Always make incremental, external back-ups of your work.