CS6 suden erratic behaviour (text problem)

Hello, I am on Windows 10, and today I suddenly have a problem with a Photoshop document (CS6), which shows erratic behavior when I select a text : it changes it completely; or when I want to transform text layers, they are systematically changed (fonts, sizes, position, text...) and seem to be replaced by other text layers that already existed in that document (but resized and reoriented in a haphazard and random way), even when I removed these texts layers they still manufest this way, changing the existing text layers when I want to modify them. Even after resetting all the tools, the problem persists. Same if I close the document and open again, the problem remains. It's terrible, I can't do anything anymore... please help me. Thank you !