Lost all edits after catalogue repair

"Really not sure why Abobe cant produce better coding. theyve been doing it for decades?

Abobe's coding is fine. But - as anyone with any database knowledge knows - sometimes databases (especially big ones) wig out for no apparent good reason. 

That's why you have back-ups: they're hardly a concept unique to Adobe, so the idea that we're looking at incompetent coding here bears little critical analysis.

Sidecar files have nothing to do with this. Lightroom can write to them if you want to, but it does not use them (unless you choose the 'read metadata from files' menu). Edits are stored in the catalog, so it sounds like the catalog the repair attempt failed. Indeed use a catalog backup.

If you also saved the edits to XMP sidecars, then you need to use 'Read Metadata from file', which can be found under the Library module's 'Metadata' menu. However, before attempting this I suggest you do as @Thor Egil Leirtrø mentioned and use a backup of your catalog.

Go back to yesterdays backup - or as many days back you need to find a working catalogue.