'Saving as backup' has deleted my colour palettes and all my work before a deadline

Hi. This is so, so important, if anyone could spend some time helping me that would be really appreciated.

I’ve been working on this project for weeks now, and the deadline is in two weeks time. I have created a sketch layer of animation around 2 minutes long and a rotoscoped moving background. For these layers, I have used colours I saved in my palette to create them.
Worried I was going to lose my work if the file corrupted, I clicked ‘save as backup’ to hopefully create another version of my work. Doing this has deleted the palette of around 12 colours and there’s no way I can see that can get it back. I am desperate, and I’ve tried for so long to create this work, and it’s all gone. Please, if anyone knows what to do, let me know. This sucks because I was being cautious, too.
Thank you so much.

These support forums seem very useful.