i had this happen after moving around some files some time ago. in my case i was pretty sure that I was indeed the issue. I read online to remove the .godot file from the project folder and then reimport the whole project.
The issue was resolved in my case if i remember, maybe it was just moving the correct files back.... sorry i cant remember. Luckily for me it was on a copy of my project i was testing around ideas on, but since that happened i have made a backup of my file every time i reach a good development point... bc that is a terrible feeling to have, and i genuinely feel bad for you. I hope something works out!