Need help:all fields are missing after deleting external data source

[ssseeesss]

I have a solution with separate data and interface files. The interface file is linked to the data file through external data source.

I accidentally deleted the external data source in the interface file and the interface file is totally messed up. All fields are missing and can't be recovered even when I put back the external data source link.

What should I do? I can either manually remap all fields (too much work, hundreds of layouts, scripts and TOs) or start from backup files (lost a few days of work).

Any other suggestions please.