The theme suddenly changed. All customization lost


Hello folks,
I have no idea why the layout suddenly changed. I remember I select the supermarket demo homelayout v3, but now it shows fashion demo in the theme option. I can’t change it, and all my previous customization has gone.
The only thing I did before the layout change is changing the header logo. Does anyone help how to restore to the previous layout and restore my previous customizations? Thanks very much