I worked on something using photoshop, and then i accidentally saved it as a PNG, which then i quickly saved it again as a PSD file. Closed the photoshop, and turned of my laptop. The next day, i open it with photoshop, it says "Not a PNG File". When i check the file type, it is PNG. But then i remember, that yesterday i saved it as a PSD. Is this a bug or something? Is there any way to fix this?